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Sample records for spoiled gradient-recalled echo

  1. Two-Dimensional Spoiled Gradient-Recalled Echo Magnetic Resonance Imaging of the Liver Using Respiratory Navigator-Gating Techniques.

    Science.gov (United States)

    Inoue, Yusuke; Hata, Hirofumi; Matsunaga, Keiji; Nakajima, Ai; Komi, Shotaro; Abe, Yutaka; Miyatake, Hiroki

    We assessed the feasibility of T1-weighted 2-dimensional spoiled gradient-recalled (2D SPGR) acquisition in steady-state imaging of the liver with various respiratory navigator gating techniques. A total of 12 healthy volunteers underwent in-phase and out-of-phase 2D SPGR imaging of the liver during breath-holding and free-breathing. Four techniques for respiratory navigation, 2 conventional navigator techniques and 2 self-navigator techniques, were used for free-breathing imaging. Good navigator waveforms were obtained in conventional navigation, whereas fluctuations were evident in self navigation. All of the 4 navigator-based methods provided better images in terms of background signals and visual image quality compared with images obtained with no respiratory control. However, differences remained in comparison with breath-holding. Superiority of self-navigation to conventional navigation was not shown. Navigator-gating techniques improved 2D SPGR images of the liver acquired during free-breathing, suggesting feasibility and beneficial effects, although navigator-based images were still inferior to breath-hold images.

  2. An analysis of the uncertainty and bias in DCE-MRI measurements using the spoiled gradient-recalled echo pulse sequence

    International Nuclear Information System (INIS)

    Subashi, Ergys; Choudhury, Kingshuk R.; Johnson, G. Allan

    2014-01-01

    Purpose: The pharmacokinetic parameters derived from dynamic contrast-enhanced (DCE) MRI have been used in more than 100 phase I trials and investigator led studies. A comparison of the absolute values of these quantities requires an estimation of their respective probability distribution function (PDF). The statistical variation of the DCE-MRI measurement is analyzed by considering the fundamental sources of error in the MR signal intensity acquired with the spoiled gradient-echo (SPGR) pulse sequence. Methods: The variance in the SPGR signal intensity arises from quadrature detection and excitation flip angle inconsistency. The noise power was measured in 11 phantoms of contrast agent concentration in the range [0–1] mM (in steps of 0.1 mM) and in onein vivo acquisition of a tumor-bearing mouse. The distribution of the flip angle was determined in a uniform 10 mM CuSO 4 phantom using the spin echo double angle method. The PDF of a wide range of T1 values measured with the varying flip angle (VFA) technique was estimated through numerical simulations of the SPGR equation. The resultant uncertainty in contrast agent concentration was incorporated in the most common model of tracer exchange kinetics and the PDF of the derived pharmacokinetic parameters was studied numerically. Results: The VFA method is an unbiased technique for measuringT1 only in the absence of bias in excitation flip angle. The time-dependent concentration of the contrast agent measured in vivo is within the theoretically predicted uncertainty. The uncertainty in measuring K trans with SPGR pulse sequences is of the same order, but always higher than, the uncertainty in measuring the pre-injection longitudinal relaxation time (T1 0 ). The lowest achievable bias/uncertainty in estimating this parameter is approximately 20%–70% higher than the bias/uncertainty in the measurement of the pre-injection T1 map. The fractional volume parameters derived from the extended Tofts model were found to be

  3. Increased flow sensitivity from gradient recalled echoes and short TRs

    International Nuclear Information System (INIS)

    Hearshen, D.O.; Froelich, J.W.; Wehrli, F.W.; Haggar, A.M.; Shimakawa, A.

    1986-01-01

    Time-of-flight effects from flow have been characterized in spin-echo images. ''Paradoxical'' enhancement and flow void are observed. Similar enhancement is seen on GRASS images. With no flow void and gradients existing throughout the volume, spins experiencing radio-frequency pulses will give rise to signals even for fast flow, providing a greater velocity sensitivity. GRASS images were obtained from a volunteer with a blood pressure cuff placed over the right thigh. With the cuff inflated, flow in the popliteal vein results in signal saturation. Increasing TR increases intensity in the popliteal vein relative to other vessels. This suggests a clinical role for the technique in assessment of slow flow

  4. MR imaging of hyperacute intracranial hematomas; Utility of gradient-recalled-echo on 0. 5 T

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Takahiko; Nishino, Shigeki; Tsuchida, Shouhei; Kinugasa, Kazushi; Asari, Shoji; Nishimoto, Akira (Okayama Univ. (Japan). School of Medicine); Akioka, Tatsurou; Sano, Masao

    1990-10-01

    A modification of the gradient-recalled-echo (GRE) pulse sequence, which we called hematoma sensitive GRE, was compared with CT and spin-echo (SE) MR images for patients suffering from parenchymal hemorrhage in the hyperacute stage (within 6 hours). In the hyperacute stage, CT was most sensitive to hematoma, and hematomas were visualized more clearly on GRE than SE. Hematomas and the surrounding tissues were almost isointense relative to white matter on T{sub 1}-weighted images (WI), and hyperintense on T{sub 2}-WI of SE. But they were visualized at different intensity from each other on GRE. Hematomas were hyperintense including hypointensity, and plasma was more hyperintense (similar to cerebrospinal fluid), and edematous tissue was slightly hyperintense relative to white matter. The changes of tissue surrounding hematoma were not detected on CT. Hematomas were iso- or hyperintense on SE in the acue stage, and were slightly hyperintense including hypointense areas with a surrounding hypointense rim on GRE. The change of intensity of hematoma was delayed on GRE compared to SE. This phenomenon was caused by lack of sensitivity to the intracellular methemoglobin. Thus it is possible to visualize the contents of hematoma on GRE in the acute stage. (author).

  5. Snapshot gradient-recalled echo-planar images of rat brains at long echo time at 9.4 T.

    Science.gov (United States)

    Lei, Hongxia; Mlynárik, Vladimir; Just, Nathalie; Gruetter, Rolf

    2008-09-01

    With improved B 0 homogeneity along with satisfactory gradient performance at high magnetic fields, snapshot gradient-recalled echo-planar imaging (GRE-EPI) would perform at long echo times (TEs) on the order of T2*, which intrinsically allows obtaining strongly T2*-weighted images with embedded substantial anatomical details in ultrashort time. The aim of this study was to investigate the feasibility and quality of long TE snapshot GRE-EPI images of rat brain at 9.4 T. When compensating for B 0 inhomogeneities, especially second-order shim terms, a 200 x 200 microm2 in-plane resolution image was reproducibly obtained at long TE (>25 ms). The resulting coronal images at 30 ms had diminished geometric distortions and, thus, embedded substantial anatomical details. Concurrently with the very consistent stability, such GRE-EPI images should permit to resolve functional data not only with high specificity but also with substantial anatomical details, therefore allowing coregistration of the acquired functional data on the same image data set.

  6. Retrospective comparison of gradient recalled echo R2* and spin-echo R2 magnetic resonance analysis methods for estimating liver iron content in children and adolescents

    Energy Technology Data Exchange (ETDEWEB)

    Serai, Suraj D.; Fleck, Robert J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, MLC 5031, Cincinnati, OH (United States); Quinn, Charles T. [Cincinnati Children' s Hospital Medical Center, Division of Hematology, Cincinnati, OH (United States); Zhang, Bin [Cincinnati Children' s Hospital Medical Center, Division of Biostatistics and Epidemiology, Cincinnati, OH (United States); Podberesky, Daniel J. [Nemours Children' s Health System Nemours Children' s Hospital, Department of Radiology, Orlando, FL (United States)

    2015-10-15

    Serial surveillance of liver iron concentration (LIC) provides guidance for chelation therapy in patients with iron overload. The diagnosis of iron overload traditionally relies on core liver biopsy, which is limited by invasiveness, sampling error, cost and general poor acceptance by pediatric patients and parents. Thus noninvasive diagnostic methods such as MRI are highly attractive for quantification of liver iron concentration. To compare two MRI-based methods for liver iron quantification in children. 64 studies on 48 children and young adults (age range 4-21 years) were examined by gradient recalled echo (GRE) R2* and spin-echo R2 MRI at 1.5T to evaluate liver iron concentration. Scatter plots and Bland-Altman difference plots were generated to display and assess the relationship between the methods. With the protocols used in this investigation, Bland-Altman agreement between the methods is best when LIC is <20 mg/g dry tissue. Scatter plots show that all values with LIC <20 mg/g dry tissue fall within the 95% prediction limits. Liver iron concentration as determined by the R2* and R2 MR methods is statistically comparable, with no statistical difference between these methods for LIC <20 mg/g. (orig.)

  7. Comparison of spin-echo echoplanar imaging and gradient recalled echo-based MR elastography at 3 Tesla with and without gadoxetic acid administration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Seek [Chonbuk National University Medical School and Hospital, Department of Radiology, Jeonju, Chonbuk (Korea, Republic of); Song, Ji Soo [Chonbuk National University Medical School and Hospital, Department of Radiology, Jeonju, Chonbuk (Korea, Republic of); Research Institute of Clinical Medicine of Chonbuk National University, Jeonju, Chonbuk (Korea, Republic of); Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Chonbuk (Korea, Republic of); Kannengiesser, Stephan [Siemens Healthcare, MR Applications Development, Erlangen (Germany); Seo, Seung Young [Research Institute of Clinical Medicine of Chonbuk National University, Jeonju, Chonbuk (Korea, Republic of); Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Chonbuk (Korea, Republic of); Chonbuk National University Medical School and Hospital, Department of Internal Medicine, Jeonju (Korea, Republic of)

    2017-10-15

    To compare spin-echo echoplanar imaging (SE-EPI) and gradient recalled echo (GRE) MR elastography (MRE) at 3 T with and without gadoxetic acid administration. We included 84 patients who underwent MRE before and after gadoxetic acid administration, each time using SE-EPI and GRE sequences. Diagnostic performance for predicting clinical liver cirrhosis and high-risk oesophageal varices was assessed using the area under the receiver-operating characteristic curve (AUC). The relationships between T2* and success of MRE, and correlations of liver stiffness (LS) values between the two sequences or before and after gadoxetic acid administration, were investigated. SE-EPI-MRE resulted in a significantly lower failure rate than GRE-MRE (1.19% vs. 10.71%, P = 0.018). Increased T2* was related to higher probability of successful LS measurement (odds ratio, 1.426; P = 0.004). The AUC of SE-EPI-MRE was comparable to that of GRE-MRE for the detection of clinical liver cirrhosis (0.938 vs. 0.948, P = 0.235) and high-risk oesophageal varices (0.839 vs. 0.752, P = 0.354). LS values were not significantly different before and after gadoxetic acid administration. SE-EPI-MRE can substitute for GRE-MRE for the detection of clinical liver cirrhosis and high-risk oesophageal varices. SE-EPI-MRE is particularly useful in patients with iron deposition, with lower failure rates than GRE-MRE. (orig.)

  8. Diagnostic accuracy of dual-echo (in- and opposed-phase) T1-weighted gradient recalled echo for detection and grading of hepatic iron using quantitative and visual assessment

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    Schieda, Nicola; Ramanathan, Subramaniyan; Ryan, John; Khanna, Maneesh; Virmani, Vivek; Avruch, Leonard [The University of Ottawa, The Ottawa Hospital, Ottawa, Ontario (Canada)

    2014-07-15

    Detection and quantification of hepatic iron with dual-echo gradient recalled echo (GRE) has been proposed as a rapid alternative to other magnetic resonance imaging (MRI) techniques. Co-existing steatosis and T1 weighting are limitations. This study assesses the accuracy of routine dual-echo GRE. Between 2010 and 2013, 109 consecutive patients underwent multi-echo (ME) MRI and dual-echo GRE for quantification of hepatic iron. Liver iron concentration (LIC) was calculated from ME-MRI. Relative signal intensity (RSI) and fat signal fraction (FSF) were calculated from dual-echo GRE. Four radiologists subjectively evaluated dual-echo GRE (±subtraction). Diagnostic accuracy was compared between techniques and correlated with biopsy using Fisher's exact test, Spearman correlation and regression. The sensitivity of visual detection of iron ranged from 48 to 55 %. Subtraction did not increase sensitivity (p < 0.001). Inter-observer variability was substantial (κ = 0.72). The specificity of visual detection of iron approached 100 % with false-positive diagnoses observed using subtraction. LIC showed a higher correlation with histopathological iron grade (r = 0.94, p < 0.001) compared with RSI (r = 0.65, p = 0.02). Univariate regression showed an association between RSI and LIC (B = 0.98, p < 0.001, CI 0.73-1.23); however, the association was not significant with multi-variate regression including FSF (p = 0.28). Dual-echo GRE has low sensitivity for hepatic iron. Subtraction imaging can result in false-positive diagnoses. (orig.)

  9. [In-phase and out-of-phase single-shot magnetization-prepared gradient recalled echo: description and optimization of technique at 1.5 T].

    Science.gov (United States)

    Ramalho, M; Herédia, V; de Campos, R O P; de Toni, M; Dale, B M; Semelka, R C

    2014-01-01

    To implement in-phase and out-of-phase (IP/OP) techniques with Magnetization-Prepared Gradient Recalled Echo (MP-GRE) and to evaluate the feasibility and diagnostic image quality among pre and post-optimized MP-GRE sequences, including patients unable to cooperate with breath-hold requirements. Institutional review board approval with waiver of informed consent was obtained for this HIPAA-compliant retrospective study. Two groups of patients were included in the study, before and after optimization of MP-GRE parameters, with seventy-three (24 noncooperative/49 cooperative) and sixty-four (22 noncooperative/42 cooperative) consecutive patients, respectively. The motion-insensitive sequence used in this study was a single-shot 2D MP-GRE. Two radiologists qualitatively evaluated the sequences to identify the presence of phase cancellation artifact in OP images and to determine image quality, extent of artifacts (respiratory ghosting, bounce-point artifact, spatial misregistration and pixel graininess) and lesion conspicuity on the various sequences. The ability to visually detect liver steatosis and fatty adrenal adenomas was evaluated. Qualitative analyses were compared using the Wilcoxon and Mann-Whitney tests. There were statistically significant differences between all MP-GRE sequences concerning phase cancellation artifact (P<.0001) which was present in MP-GRE OP sequences and negligible to absent in the pre (IP1) and post-optimized (IP2) MP-GRE IP sequences, respectively, in all patients. Bounce point artifacts were significantly more pronounced in MP-GRE IP1 (P<.0001). Spatial misregistration was slightly more prominent in noncooperative patients with MP-GRE IP2 (P=.0027). MP-GRE OP and MP-GRE IP2 showed significantly higher overall image quality (P<.0001). MP-GRE sequences subjectively identified hepatic steatosis (n=20) and adrenal adenomas (n=5) based on signal loss from IP to OP sequence. Single shot IP/OP MP-GRE is feasible and allows motion resistant

  10. Assessment of microstructural signal compartments across the corpus callosum using multi-echo gradient recalled echo at 7 T.

    Science.gov (United States)

    Thapaliya, Kiran; Vegh, Viktor; Bollmann, Steffen; Barth, Markus

    2017-11-26

    Quantitative assessment of tissue microstructure is important in studying human brain diseases and disorders in which white matter is implicated, as it has been linked to demyelination, re-myelination, and axonal damage in clinical conditions. Ultra-high field magnetic resonance imaging data obtained using a multi-echo gradient echo sequence has been shown to contain information on myelin, axonal and extracellular compartments in white matter. In this study, we aimed to assess the sensitivity of a three-compartment model to estimate the variation of corresponding compartment parameters (water fraction, relaxation time and frequency shift) of the corpus callosum sub-regions, which are known to have different tissue structure. Additionally, we computed the g-ratio using myelin and axonal water fractions and performed a voxel-by-voxel analysis in the corpus callosum. Based on data acquired for ten participants, we show that the myelin compartment water fraction and T 2 ∗ is consistent across the corpus callosum sub-regions, whilst myelin frequency shift varies. The results show that the variation in water fraction, T 2 ∗ and frequency shift for the myelin signal compartment across the corpus callosum is smaller than for the axonal and extracellular signal compartments. The computed g-ratio was comparable to previously published studies in the corpus callosum. Our study suggests that a multi-echo GRE approach in vivo combined with a complex three-compartment model is sensitive to microstructural parameter variations across the human corpus callosum. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Liver Lobe Based Multi-Echo Gradient Recalled Echo T2*-Weighted Imaging in Chronic Hepatitis B-Related Cirrhosis: Association with the Presence and Child-Pugh Class of Cirrhosis.

    Directory of Open Access Journals (Sweden)

    Dan Wang

    Full Text Available To investigate whether liver lobe based T2* values measured on gradient recalled echo T2*-weighted imaging are associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis.Fifty-six patients with hepatitis B-related cirrhosis and 23 healthy control individuals were enrolled in this study and underwent upper abdominal T2*-weighted magnetic resonance imaging. T2* values of the left lateral lobe (LLL, left medial lobe (LML, right lobe (RL and caudate lobe (CL were measured on T2*-weighted imaging. Statistical analyses were performed to determine the association between liver lobe based T2* values and the presence and Child-Pugh class of cirrhosis.The T2* values of the LLL, LML and RL decreased with the progression of cirrhosis from Child-Pugh class A to C (r = -0.231, -0.223, and -0.395, respectively; all P 0.05. To a certain extent, Mann-Whitney U tests with Bonferroni correction for multigroup comparisons showed that the T2* values of the LLL, LML and RL could distinguish cirrhotic liver from healthy liver (all P 0.05. Receiver operating characteristic analysis demonstrated that the T2* value of the RL could best distinguish cirrhosis from healthy liver, with an area under the receiver operating characteristic curve (AUC of 0.713 among T2* values of the liver lobes, and that only the T2* value of the RL could distinguish Child-Pugh class C from A-B, with an AUC of 0.697 (all P < 0.05.The T2* value of the RL can be associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis.

  12. Reduction of Flow Artifacts by Using Partial Saturation in RF-Spoiled Gradient-Echo Imaging

    OpenAIRE

    Han, Misung; Hargreaves, Brian A.

    2011-01-01

    Radiofrequency (RF)-spoiled gradient-echo imaging provides a signal intensity close to pure T1 contrast by using spoiler gradients and RF phase cycling to eliminate net transverse magnetization. Generally, spins require many RF excitations to reach a steady-state magnetization level; therefore, when unsaturated flowing spins enter the imaging slab, they can cause undesirable signal enhancement and generate image artifacts. These artifacts can be reduced by partially saturating an outer slab u...

  13. Reduction of flow artifacts by using partial saturation in RF-spoiled gradient-echo imaging.

    Science.gov (United States)

    Han, Misung; Hargreaves, Brian A

    2011-05-01

    Radiofrequency (RF)-spoiled gradient-echo imaging provides a signal intensity close to pure T(1) contrast by using spoiler gradients and RF phase cycling to eliminate net transverse magnetization. Generally, spins require many RF excitations to reach a steady-state magnetization level; therefore, when unsaturated flowing spins enter the imaging slab, they can cause undesirable signal enhancement and generate image artifacts. These artifacts can be reduced by partially saturating an outer slab upstream to drive the longitudinal magnetization close to the steady state, while the partially saturated spins generate no signal until they enter the imaging slab. In this work, magnetization evolution of flowing spins in RF-spoiled gradient-echo sequences with and without partial saturation was simulated using the Bloch equations. Next, the simulations were validated by phantom and in vivo experiments. For phantom experiments, a pulsatile flow phantom was used to test partial saturation for a range of flip angles and relaxation times. For in vivo experiments, the technique was used to image the carotid arteries, abdominal aorta, and femoral arteries of normal volunteers. All experiments demonstrated that partial saturation can provide consistent T(1) contrast across the slab while reducing inflow artifacts. Copyright © 2011 Wiley-Liss, Inc.

  14. Multiparameter estimation using multi-echo spoiled gradient echo with variable flip angles and multicontrast compressed sensing.

    Science.gov (United States)

    Tamada, Daiki; Wakayama, Tetsuya; Onishi, Hiroshi; Motosugi, Utaroh

    2018-02-24

    To develop multiparameter mapping including T 1 , R2*, and proton density fat fraction with a single breath-hold to evaluate liver disease and liver function. A 6-echo spoiled gradient-echo sequence with dual flip angles was used to acquire a 12-set MRI volume data set. To shorten the scan time, undersampling and multicontrast compressed-sensing reconstruction were used. The scan time was 18 seconds. R2* and proton density fat fraction mapping were achieved by using the iterative least-squares method. T 1 mapping was estimated using driven equilibrium single-pulse observation of T 1 . Quantitative values were validated by performing phantom and volunteer studies. Statistical analysis showed that the quantitative values measured using the proposed methods agreed with those measured using conventional methods. T 1 values of water proton measured by the proposed method in phantom and volunteer studies were in good agreement with those by MRS. The results showed that accurate quantitative mapping of T 1 , R2*, and proton density fat fraction with a single breath-hold was achieved using our approach. © 2018 International Society for Magnetic Resonance in Medicine.

  15. In vivo quantitative NMR imaging of fruit tissues during growth using Spoiled Gradient Echo sequence

    DEFF Research Database (Denmark)

    Kenouche, S.; Perrier, M.; Bertin, N.

    2014-01-01

    the intrinsic parameters maps M 0 and T 1 of the fruit tissues. Water transport and paths flow were monitored using Gd 3+/[Fe(CN)6]3-/D - mannitol nanoparticles as a tracer. This dynamic study was carried out using a compartmental modeling. The CA was preferentially accumulated in the surrounding tissues...... of this study was to design a robust and accurate quantitative measurement method based on NMR imaging combined with contrast agent (CA) for mapping and quantifying water transport in growing cherry tomato fruits. A multiple flip-angle Spoiled Gradient Echo (SGE) imaging sequence was used to evaluate...... of columella and in the seed envelopes. The total quantities and the average volume flow of water estimated are: 198 mg, 1.76 mm 3/h for the columella and 326 mg, 2.91 mm 3/h for the seed envelopes. We demonstrate in this paper that the NMR imaging technique coupled with efficient and biocompatible CA...

  16. Data-driven optimized flip angle selection for T1 estimation from spoiled gradient echo acquisitions.

    Science.gov (United States)

    Lewis, Christina M; Hurley, Samuel A; Meyerand, M Elizabeth; Koay, Cheng Guan

    2016-09-01

    Define criteria for selection of optimal flip angle sets for T1 estimation and evaluate effects on T1 mapping. Flip angle sets for spoiled gradient echo-based T1 mapping were selected by minimizing T1 estimate variance weighted by the joint density of M0 and T1 in an initial acquisition. The effect of optimized flip angle selection on T1 estimate error was measured using simulations and experimental data in the human and rat brain. For two-point acquisitions, optimized angle sets were similar to those proposed by other groups and, therefore, performed similarly. For multipoint acquisitions, optimal angle sets for T1 mapping in the brain consisted of a repetition of two angles. Implementation of optimal angles reduced T1 estimate variance by 30-40% compared with a multipoint acquisition using a range of angles. Performance of the optimal angle set was equivalent to that of a repetition of the two-angle set selected using criteria proposed by other researchers. Repetition of two carefully selected flip angles notably improves the precision of resulting T1 estimates compared with acquisitions using a range of flip angles. This work provides a flexible and widely applicable optimization method of particular use for those who repeatedly perform T1 estimation. Magn Reson Med 76:792-802, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  17. Minimum TE gradient-recalled phosphorus imaging sequence on a whole-body imager

    International Nuclear Information System (INIS)

    Listerud, J.; Lenkinski, R.E.; Axel, L.

    1989-01-01

    To define the lower limits of spatial resolution in gradient-recalled echo phosphorus studies at 1.5 T, the authors have implemented a phosphorus gradient-recalled imaging sequence on the Signa imager. All gradient ramps for the section-selective rephasing lobe, the phase-encoding pulse, and the dephasing pulse of the frequency-encoding gradient are slowed at the maximal rate. Consequently, with a field of view of 24 cm, an in-plane resolution of 3 cm, an echo appropriately offset, an RF bandwidth of 1.2 KHz, and a section thickness of 5 cm, the echo time may be reduced to 1.35 msec. The reconstruction algorithm has been modified to support oversampled data of low spatial resolution appropriate for phosphorus imaging. The sequence will acquire H-1 images and supports the automatic and manual prescan features of the commercial instrument. To facilitate setup in the phosphorus imaging mode the sequence supports the product spectroscopic mode with a DRESS (depth recalled surface coil spectroscopy) sequence and a section profile sequence for appropriate shimming, receiver characteristics, and averaging requirements. The suitability for adaptation of this sequence to three-dimensional chemical shift imaging is discussed

  18. New spoiled spin-echo technique for three-dimensional MR imaging

    International Nuclear Information System (INIS)

    Darrasse, L.; Mao, L.; Saint-Jalmes, H.

    1989-01-01

    For 3D MR imaging within a convenient scanning time, the authors propose an improved spin-echo technique that permits the use of TRs shorter than 100 msec. They use a two-pulse RF sequence (α-π echo). The echo is read with conventional 3DFT encoding. To avoid steady-state signal refocusing before either α or (imperfect) π pulses, we apply randomized gradient spoilers both before each α pulse and on each side of the π pulse. So the sequence works like standard spin- echo sequences, with the z-magnetization recovery being adjusted by means of α rather than TR. The authors have investigated the method on a new 0.1-T Magnetom system dedicated for 3D MR imaging

  19. Relationship between the trochlear groove angle and patellar cartilage morphology defined by 3D spoiled gradient-echo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Yuko; Tokuda, Osamu; Matsunaga, Naofumi [Yamaguchi University Graduate School of Medicine, Department of Radiology, Yamaguchi (Japan); Fukuda, Kouji [Shunan Memorial Hospital, Division of Radiological Technology, Yamaguchi (Japan); Shiraishi, Gen; Motomura, Tetsuhisa [Shunan Memorial Hospital, Department of Orthopedics Surgery, Yamaguchi (Japan); Kimura, Motoichi [Customer Application Gr., GE Healthcare MR Sales and Marketing Department, Osaka (Japan)

    2012-05-15

    To examine whether the femoral trochlear groove angle (TGA) is a determinant of the patellar cartilage volume and patellar cartilage damage. Patellar cartilage was evaluated by MR imaging in 66 patients (22 males and 44 females) with knee pain. Fat-suppressed 3D spoiled gradient-echo images were used to calculate the cartilage volume and to grade the cartilage damage. The proximal and distal TGAs were measured from axial PD-weighted FSE MR images with fat suppression. For every increase in the TGA at the distal femur, the patellar cartilage volume was significantly increased by 6.07 x 10{sup -3} cm{sup 3} (95% CI: 1.27 x 10{sup -3}, 10.9 x 10{sup -3}) after adjustment for age, gender, and patellar bone volume (P < 0.05). The MR grade of medial patellar cartilage damage progressed as the distal TGA became narrower, although there was no significant correlation between the distal TGA and the MR grading of patellar cartilage damage. A more flattened distal TGA was associated with increased patellar cartilage volume. However, there was no association between TGA and patellar cartilage defects. (orig.)

  20. Echo

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    Harvey, Dustin Yewell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-25

    This document is a white paper marketing proposal for Echo™ is a data analysis platform designed for efficient, robust, and scalable creation and execution of complex workflows. Echo’s analysis management system refers to the ability to track, understand, and reproduce workflows used for arriving at results and decisions. Echo improves on traditional scripted data analysis in MATLAB, Python, R, and other languages to allow analysts to make better use of their time. Additionally, the Echo platform provides a powerful data management and curation solution allowing analysts to quickly find, access, and consume datasets. After two years of development and a first release in early 2016, Echo is now available for use with many data types in a wide range of application domains. Echo provides tools that allow users to focus on data analysis and decisions with confidence that results are reported accurately.

  1. Utility of gradient recalled echo magnetic resonance imaging for the study of myelination in cuprizone mice treated with fingolimod.

    Science.gov (United States)

    Ziser, Laura; Meyer-Schell, Naja; Kurniawan, Nyoman D; Sullivan, Robert; Reutens, David; Chen, Min; Vegh, Viktor

    2018-03-01

    The availability of high-field-strength magnetic resonance imaging (MRI) systems has brought about the development of techniques that aim to map myelination via the exploitation of various contrast mechanisms. Myelin mapping techniques have the potential to provide tools for the diagnosis and treatment of diseases, such as multiple sclerosis. In this study, we evaluated the sensitivity of T 2 *, frequency shift and susceptibility measures to myelin levels in a cuprizone mouse model of demyelination. The model was supplemented with two different dosages of fingolimod, a drug known to positively affect demyelination. A decrease in grey-white matter contrast with the cuprizone diet was observed for T 2 *, frequency shift and susceptibility measures, together with myelin basic protein antibody findings. These results indicate that T 2 *, frequency shift and susceptibility measures have the potential to act as biomarkers for myelination. Susceptibility was found to be the most sensitive measure to changes in grey-white matter contrast. In addition, fingolimod treatment was found to reduce the level of demyelination, with a larger dosage exhibiting a greater reduction in demyelination for the in vivo MRI results. Overall, susceptibility mapping appears to be a more promising tool than T 2 * or frequency shift mapping for the early diagnosis and treatment of diseases in which myelination is implicated. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Spoils of Truce

    DEFF Research Database (Denmark)

    Haugbølle, Sune

    2014-01-01

    Review of Spoils of Truce. Corruption and stat building in Postwar Lebanon Reinoud Leenders Ithaca, NY, Cornell University Press, 2012, ISBN 978-0-8014-5100-3......Review of Spoils of Truce. Corruption and stat building in Postwar Lebanon Reinoud Leenders Ithaca, NY, Cornell University Press, 2012, ISBN 978-0-8014-5100-3...

  3. Sensitivity of 3D gradient recalled echo susceptibility-weighted imaging technique compared to computed tomography angiography for detection of middle cerebral artery thrombus in acute stroke

    Directory of Open Access Journals (Sweden)

    Amit Agarwal

    2014-11-01

    Full Text Available We aimed at comparing the sensitivity of magnetic resonance (MR susceptibility-weighted imaging (SWI with computed tomography angiography (CTA in the detection of middle cerebral artery (MCA thrombus in acute stroke. Seventy-nine patients with acute MCA stroke was selected using our search engine software; only the ones showing restricted diffusion in the MCA territory on diffusion-weighted images were included. We finally selected 35 patients who had done both MRI (including SWI and CTA. Twenty random subjects with completely normal MRI (including SWI exam were selected as control. Two neuroradiologists (blinded to the presence or absence of stroke reviewed the SW images and then compared the findings with CT angiogram (in patients with stroke. The number of MCA segments showing thrombus in each patient was tabulated to estimate the thrombus burden. Thrombus was detected on SWI in one or more MCA segments in 30 out of 35 patients, on the first review. Of the 30, SWI showed thrombus in more than one MCA segments in 7 patients. CTA depicted branch occlusion in 31 cases. Thrombus was seen on both SWI and CTA in 28 patients. Thrombus was noted in two patients on SWI only, with no corresponding abnormality seen on CTA. Two patients with acute MCA showed no vascular occlusion or thrombus on either CTA or SWI. Only two case of false-positive thrombus was reported in normal control subjects. Susceptibility-weighted images had sensitivity and specificity of 86% and 90% respectively, with positive predictive value 94%. Sensitivity was 86% for SWI, compared with 89% for CTA, and this difference was statistically insignificant (P>0.05. Of all the positive cases on CTA (31 corresponding thrombus was seen on SWI in 90% of subjects (28 of 31. Susceptibility-weighted imaging has high sensitivity for detection of thrombus in acute MCA stroke. Moreover, SWI is a powerful technique for estimation of thrombus burden, which can be challenging on CTA.

  4. ECHO virus

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001340.htm ECHO virus To use the sharing features on this page, please enable JavaScript. Enteric cytopathic human orphan (ECHO) viruses are a group of viruses that can lead ...

  5. Echo project

    DEFF Research Database (Denmark)

    Gfader, Verina; Carson, Rebecca; Kraus, Chris

    2016-01-01

    Echo project (ed. by Verina Gfader and Ruth Höflich) is an online publication and community board that developed from a visit to the Los Angeles Art Book fair in January 2014. It was on the occasion of a prior book project, titled Prospectus, that the editorial team had been invited by the LAABF...... team to both present the printed matter in the format of running a book stall, and stage a discursive event at the Classroom. Echo reverberates some of the encounters and debates there, with new commissioned chapters propelling a ongoing correspondence across urban environs: An essay on the General...

  6. The biological costs of not reclaiming bentonite mine spoils

    Science.gov (United States)

    Carolyn Hull Sieg; Daniel W. Uresk; Richard M. Hansen

    1982-01-01

    Bentonite clay has been mined in the northern Great Plains for more than 80 years. Until the late 1960's, mine spoil materials were left in steep piles and no effort was made to restore biological productivity to these disturbed sites. As a result, unreclaimed spoils are barren and eroded. The biological costs of not reclaiming these spoils are examined in this...

  7. Race, Commitment to Deviance, and Spoiled Identity

    Science.gov (United States)

    Harris, Anthony R.

    1976-01-01

    Data generated by 234 young black and white inmates in 1971 challenge the assumption that spoiled identity is a necessary, socially invariant outcome of deviant commitment and self-definition. For blacks, the relationship between criminal self-typing and stability and esteem is negative but inconsequential; for whites, the relationship is negative…

  8. A Spectral Emissivity Library of Spoil Substrates

    Czech Academy of Sciences Publication Activity Database

    Pivovarník, Marek; Pikl, Miroslav; Frouz, J.; Zemek, František; Kopačková, V.; Notesco, G.; Ben Dor, E.

    2016-01-01

    Roč. 1, č. 2 (2016) E-ISSN 2306-5729 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : post- mining sites * spectral emissivity * spectral library * spoil substrates Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7)

  9. Promising native forbs for seeding on mine spoils

    Science.gov (United States)

    Ardell J. Bjugstad; Warren C. Whitman

    1989-01-01

    Twenty nine species of perennial forbs and 2 biennial forbs were directly seeded into coal mine spoil materials at Dickinson, North Dakota to determine which species would be most successful for direct seeding into coal mine spoil. Those which showed exceptionally good emergence and vigorous growth of seedlings in a two year study were: white prairie clover (...

  10. Grating stimulated echo

    International Nuclear Information System (INIS)

    Dubetsky, B.; Berman, P.R.; Sleator, T.

    1992-01-01

    A theory of a grating simulated echo (GTE) is developed. The GSE involves the sequential excitation of atoms by two counterpropagating traveling waves, a standing wave, and a third traveling wave. It is shown that the echo signal is very sensitive to small changes in atomic velocity, much more sensitive than the normal stimulated echo. Use of the GSE as a collisional probe or accelerometer is discussed

  11. Recognizing critical mine spoil health characteristics to design ...

    Science.gov (United States)

    Biochar can be used as an amendment to remediate metal-contaminated mine spoils for improved site phytostabilization. For successful phytostabilization to occur, biochar amendments must improve mine spoil health with respect to plant rooting plus uptake of water and nutrients. An inappropriate biochar may negatively impact plant growth conditions resulting in poor plant establishment and growth. Matching the appropriate biochar for each mine site requires reconnaissance of spoil chemical and physical conditions and then identifying which properties need rectified to promote plant growth. A rectification hierarchy needs to be established with the primary limiting factor being addressed first, then successive limitations addressed simultaneously or thereafter. We posit that spoils at each site will have a unique chemical, physical, and biological signature that will affect plant growth. For example, some spoils may be extremely acidic, possess phytotoxic concentrations of heavy metals, or have physical conditions that limits water storage and root penetration. Quantifying these and other conditions beforehand allows for the production of designer biochar with specific characteristics tailored for specific plant growth deficiencies within each spoil. Additionally, we recommend the use of proximally located, undisturbed soils to establish spoil remediation targets. In our work, we have developed a decision-tree flow-chart that identifies salient chemical,

  12. Happy birthday Echo!

    CERN Multimedia

    Staff Association

    2010-01-01

    You are reading the number hundred and one (no. 101) edition of our bulletin Echo. Just over four years ago, on 27th March 2006, the first untitled edition was published (Fig. 1 on the left). The title Echo appeared on the second edition on 10th April 2006 (Fig. 1 in the centre). Today (see Fig. 1 on the right), the layout is slightly different, but the structure of each edition has remained more or less the same: an editorial informing you of the important issues, followed by articles on club life, cultural activities (exhibitions and conferences), information from GAC-EPA, and special offers for our members.     Fig. 1 : Nos. 1, 2 and 100 of our twice-monthly publication Echo Echo was created in March 2006 when, much to our regret, CERN official communication and that of your representatives were separated. November 2009 saw a return to normal practice, and since then the CERN st...

  13. Groundwater hydrogeochemical characteristics in rehabilitated coalmine spoils

    Science.gov (United States)

    Gomo, M.; Masemola, E.

    2016-04-01

    The investigation aims to identify and describe hydrogeochemical processes controlling the evolution of groundwater chemistry in rehabilitated coalmine spoils and their overall influence on groundwater quality at a study area located in the Karoo basin of South Africa. A good understanding of the processes that controls the evolution of the mine water quality is vital for the planning, application and management of post-mining remedial actions. The study utilises scatter plots, statistical analysis, PHREEQC hydrogeochemical modelling, stoichiometric reaction ratios analysis, and the expanded Durov diagram as complimentary tools to interpret the groundwater chemistry data collected from monitoring boreholes from 1995 to 2014. Measured pH ranging between 6-8 and arithmetic mean of 7.32 shows that the groundwater system is characterised by circumneutral hydrogeochemical conditions period. Comparison of measured groundwater ion concentrations to theoretical reaction stoichiometry identifies Dolomite-Acid Mine Drainage (AMD) neutralisation as the main hydrogeochemical process controlling the evolution of the groundwater chemistry. Hydrogeochemical modelling shows that, the groundwater has temporal variations of calcite and dolomite saturation indices characterised by alternating cycles of over-saturation and under-saturation that is driven by the release of sulphate, calcium and magnesium ions from the carbonate-AMD neutralization process. Arithmetic mean concentrations of sulphate, calcium and magnesium are in the order of 762 mg/L, 141 mg/L and 108 mg/L. Calcium and magnesium ions contribute to very hard groundwater quality conditions. Classification based on total dissolved solids (TDS), shows the circumneutral water is of poor to unacceptable quality for drinking purposes. Despite its ability to prevent AMD formation and leaching of metals, the dolomite-AMD neutralisation process can still lead to problems of elevated TDS and hardness which mines should be aware of

  14. Phytoremediation of coal mine spoil dump through integrated biotechnological approach

    Energy Technology Data Exchange (ETDEWEB)

    Juwarkar, A.A.; Jambhulkar, H.P. [National Environmental Engineering Research Institute, Nagpur (India)

    2008-07-15

    Field experiment was conducted on mine spoil dump on an area of 10 ha, to restore the fertility and productivity of the coal mine spoil dump using integrated biotechnological approach. The approach involves use of effluent treatment plant sludge (ETP sludge), as an organic amendment, biofertilizers and mycorrihzal fungi along with suitable plant species. The results of the study indicated that amendment with effluent treatment plant sludge (ETP sludge), at 50 ton/ha improved the physico-chemical properties of coal mine spoil. Due to biofertilizer inoculation different microbial groups such as Rhizobium, Azotobacter and VAM spores, which were practically absent in mine spoil improved greatly. Inoculation of biofertilizer and application of ETP sludge helped in reducing the toxicity of heavy metals such as chromium, zinc, copper, iron, manganese lead, nickel and cadmium, which were significantly reduced to 41%, 43%, 37%, 37%, 34%, 39%, 37% and 40%, respectively, due to the increased organic matter content in the ETP sludge and its alkaline pH (8.10-8.28), at which the metals gets immobilized and translocation of metals is arrested. Thus, amendment and biofertilizer application provided better supportive material for anchorage and growth of the plant on coal mine spoil dump.

  15. 30 CFR 816.73 - Disposal of excess spoil: Durable rock fills.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Disposal of excess spoil: Durable rock fills...-SURFACE MINING ACTIVITIES § 816.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

  16. 30 CFR 817.73 - Disposal of excess spoil: Durable rock fills.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Disposal of excess spoil: Durable rock fills...-UNDERGROUND MINING ACTIVITIES § 817.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

  17. The Characteristics and Fertility Status of Tin Mine Spoils of the Jos ...

    African Journals Online (AJOL)

    ... include reclaimed cropped spoil (RCS), reclaimed uncropped spoil (RUS), mining (intermound) depressions (MD), spoil mounds (SM) and surrounding flat land (SFL). Unmined Ropp soil (URS) was included as control. RCS had significantly (P < 0.05) higher amounts of total nitrogen (1.6 g kg-1) and organic carbon (13.7 ...

  18. Spoiling the womb”: Definitions, Aetiologies and responses to ...

    African Journals Online (AJOL)

    Spoiling the womb”: Definitions, Aetiologies and responses to infertility in North West Province, Cameroon. ... Now, family planning is promoted nationwide to reduce population growth, and infertility is not addressed by public health policy or services. In contrast to the biomedical definition used by planners, at the local level ...

  19. Investigation on the spoiling of meat using PTR-MS

    International Nuclear Information System (INIS)

    Mayr, D.; Maerk, T.D.; Margesin, R.; Schinner, F.

    2002-01-01

    The spoiling of meat was investigated. Beef (pork) were wrapped into different kinds of packages (air and vacuum) and stored at 4 o C for 10 (13) days. The emitted volatile organic compounds (VOCs) in the course of time were measured and a large increase in these emissions after a few days of storage was found. Also a large difference in the spoiling behavior between vacuum- and air- packed meat was observed. The measurements were performed using a proton-transfer-reaction-mass spectrometer(PTR-MS) system, it allows on-line monitoring of volatile organic compounds (VOCs) concentrations. Ethylacetate, methylpropionate, and propylformate were detected as typical spoiling compounds in pork samples. After 3.5 days the concentrations started to exponentially increase, but after 6 days remained more or less unchanged. This VOCs behaviour corresponds to a typical bacterial growth curve. Therefore, it was concluded that bacteria produce these components. In a second measurements set, the VOCs emitted by beef under aerobic (normal packed) and anaerobic (vacuum packed) conditions were compared. In the case of normal air-packed beef, the above mentioned spoiling compounds strongly increased with the time, while with the vacuum-packed beef a strong increase of ethanol was detected. This method as a replacement of the bacteriological examinations of meat spoilage is proposed. (nevyjel)

  20. stabilization of dredged spoils for pavement construction in the niger ...

    African Journals Online (AJOL)

    Dr. Tse

    to which dredge spoils can be deployed, including use as fill and construction materials, placing the dredged material at specific locations to combat erosion, and manufacturing bricks, etc. These uses will be particularly beneficial given the high rainfall intensity, extensive marsh land and frequent oil spills in the study area.

  1. 30 CFR 715.15 - Disposal of excess spoil.

    Science.gov (United States)

    2010-07-01

    ... engineer or other qualified professional specialist experienced in the construction of earth and rockfill... minesite. (11) Coal processing wastes shall not be disposed of in head-of-hollow or valley fills, and may... require a flatter slope. (c) Head-of-hollow fills. Disposal of spoil in the head-of-hollow fill shall meet...

  2. stabilization of dredged spoils for pavement construction in the niger

    African Journals Online (AJOL)

    Dr. Tse

    spoils by stabilization produces a 'conditioned' soil mix with improved strength properties suitable for use in civil engineering construction. In view of the large volumes of sand dredged from rivers along the East-West road alignment, it is thought that a beneficial scheme to use such large quantity of otherwise waste material ...

  3. Prediction of the acid generating potential of coal mining spoils

    Energy Technology Data Exchange (ETDEWEB)

    Monterroso, C.; Macias, F. [Universidad de Santiago, Santiago (Spain). Dept. de Edafologia y Quimica Agricola

    1998-07-01

    The sulfide oxidation impact on mined land reclamation makes it necessary for mine spoils to be classified according to their acidifying potential. In this paper predictions were made of the acid generating potential of sulfide-containing spoils from the Puentes lignite mine (Galicia, NW Spain), and the limits of sulfur contents allowable for their storage in aerobic conditions, were established. Using samples of fresh spoils, analyses were made of the content and speciation of sulfur, pH was measured after oxidation of the sample with H{sub 2}O{sub 2} (pH of oxidation = pH{sub OX}), and titration of the oxidation extract with 0.1N NaOH to pH = 7 was carried out (Net Acid Production = NAP). The total sulfur content (S{sub T}) varied between {lt} 0.01% and {gt} 3%, with pyritic-S being the most common form ({gt} 80%). pH{sub OX} varied between 1.6 and 6.4 and NAP between 1.2 and 85.0 Kg-CaCO{sub 3}t{sup -1}. A high correlation was found between the NAP and the S{sub T}(r-0.98, p{lt} 0.001). Spoils with S{sub T} {gt} 0.15% cause high risks of mine-soil acidification, and create the need for large doses of CaCO{sub 3} to be used on final surface of the mine dump. Use of fly ash, produced from the combustion of lignite, as an alternative to commercial lime is more effective in the control of acidity generated by spoils with high S{sub T}. 20 refs., 5 figs., 1 tab.

  4. Spin echo in synchrotrons

    Directory of Open Access Journals (Sweden)

    Alexander W. Chao

    2007-01-01

    Full Text Available As a polarized beam is accelerated through a depolarization resonance, its polarization is reduced by a well-defined calculable reduction factor. When the beam subsequently crosses a second resonance, the final beam polarization is considered to be reduced by the product of the two reduction factors corresponding to the two crossings, each calculated independently of the other. This is a good approximation when the spread of spin precession frequency Δν_{spin} of the beam (particularly due to its energy spread is sufficiently large that the spin precession phases of individual particles smear out completely during the time τ between the two crossings. This approximate picture, however, ignores two spin dynamics effects: an interference-overlap effect and a spin echo effect. This paper is to address these two effects. The interference-overlap effect occurs when Δν_{spin} is too small, or when τ is too short, to complete the smearing process. In this case, the two resonance crossings overlap each other, and the final polarization exhibits constructive or destructive interference patterns depending on the exact value of τ. Typically, the beam’s energy spread is large and this interference-overlap effect does not occur. To study this effect, therefore, it is necessary to reduce the beam energy spread and to consider two resonance crossings very close to each other. The other mechanism, also due to the interplay between two resonance crossings, is spin echo. It turns out that even when the precession phases appear to be completely smeared between the two crossings, there will still be a sudden and short-lived echo signal of beam polarization at a time τ after the second crossing; the magnitude of which can be as large as 57%. This echo signal exists even when the beam has a sizable energy spread and when τ is very large, and could be a sensitive (albeit challenging way to experimentally test the intricate spin dynamics in a synchrotron

  5. Phytoremediation of spoil coal dumps in Western Donbass (Ukraine)

    Science.gov (United States)

    Klimkina, Iryna; Kharytonov, Mykola; Wiche, Oliver; Heilmeier, Hermann

    2017-04-01

    At the moment, in Ukraine about 150 thousand hectares of fertile land are occupied by spoil dumps. Moreover, this figure increases every year. According to the technology used about 1500 m3 of adjacent stratum is dumped at the surface per every 1000 tons of coal mined. Apart from land amortization, waste dumps drastically change the natural landscape and pollute air, soil and water sources as the result of water and wind erosion, as well as self-ignition processes. A serious concern exists with respect to the Western Donbass coal mining region in Ukraine, where the coal extraction is made by the subsurface way and solid wastes are represented by both spoil dumps and wastes after coal processing. Sulphides, mostly pyrite (up to 4% of waste material), are widely distributed in the waste heaps freshly removed due to coal mining in Western Donbass.The oxidation of pyrite with the presence of oxygen and water is accompanied by a sharp drop in the pH from the surface layer to the spoil dumps(from 5.2-6.2 to 3.9-4.2 in soil substrates with chernozen and from 8.3-8.4 to 6.7-7.2 in soil substrates with red-brown clay, stabilizing in dump material in both cases at 2.9-3.2). Low pH generates the transformation of a number of toxic metals and other elementspresent in waste rock (e.g. Fe, Al, Mn, Zn, Mo, Co, As, Cd, Bi, Pb, U) into mobile forms. To stabilize and reduce metal mobility the most resistant plants that occur naturally in specified ecosystems can be used. On coal spoil dumpsin Western Donbas the dominant species are Bromopsis inermis, subdominant Artemisia austriaca; widespread are also Festucas pp., Lathyrus tuberosus, Inula sp., Calamagrostis epigeios, Lotus ucrainicus, and Vicias pp. Identification of plants tolerant to target metals is a key issue in phytotechnology for soil restoration. It is hypothesized that naturally occurring plants growing on coal spoil dumps can be candidates for phytostabilization, phytoextraction (phytoaccumulation) and phytomining

  6. Dissecting a Light Echo

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for audio animation This animation illustrates how a light echo works, and how an optical illusion of material moving outward is created. A light echo occurs when a star explodes, acting like a cosmic flashbulb. The light from this explosion zips through nearby dust clumps, illuminating and heating them up slightly. This brief period of warming causes them to glow in infrared, like a chain of Christmas bulbs lighting up one by one. The animation starts by showing the explosion of a star, which results in a flash of light that moves outward in all directions. The direction of our line of sight from Earth is indicated by the blue arrow. When the light flash reaches surrounding dust, shown here as three dark clouds, the dust is heated up, creating infrared light that begins to travel toward Earth (indicated by the red arrows). Dust closest to the explosion lights up first, while the explosion's shock wave takes longer to reach more distant material. This results in light from different parts of the cloud reaching Earth at different times, creating the illusion of motion over time. As the animation shows, the inclination of the cloud toward our line of sight can result in the material seeming to move both away from and toward the central star.

  7. Echo Cancellation I: Algorithms Simulation

    Directory of Open Access Journals (Sweden)

    P. Sovka

    2000-04-01

    Full Text Available Echo cancellation system used in mobile communications is analyzed.Convergence behavior and misadjustment of several LMS algorithms arecompared. The misadjustment means errors in filter weight estimation.The resulting echo suppression for discussed algorithms with simulatedas well as rela speech signals is evaluated. The optional echocancellation configuration is suggested.

  8. Simple Echoes and Subtle Reverberations

    Science.gov (United States)

    Keeports, David

    2010-01-01

    Reverberation within an enclosed space can be viewed as a superposition of a large number of simple echoes. The echoes that make up the sound of reverberation fall neatly into two categories, relatively loud and sparse early reflections, and relatively soft and dense late reflections. Ways in which readily available music production software can…

  9. Fast susceptibility-weighted imaging with three-dimensional short-axis propeller (SAP)-echo-planar imaging.

    Science.gov (United States)

    Holdsworth, Samantha J; Yeom, Kristen W; Moseley, Michael E; Skare, S

    2015-05-01

    Susceptibility-weighted imaging (SWI) in neuroimaging can be challenging due to long scan times of three-dimensional (3D) gradient recalled echo (GRE), while faster techniques such as 3D interleaved echo-planar imaging (iEPI) are prone to motion artifacts. Here we outline and implement a 3D short-axis propeller echo-planar imaging (SAP-EPI) trajectory as a faster, motion-correctable approach for SWI. Experiments were conducted on a 3T MRI system. The 3D SAP-EPI, 3D iEPI, and 3D GRE SWI scans were acquired on two volunteers. Controlled motion experiments were conducted to test the motion-correction capability of 3D SAP-EPI. The 3D SAP-EPI SWI data were acquired on two pediatric patients as a potential alternative to 2D GRE used clinically. The 3D GRE images had a better target resolution (0.47 × 0.94 × 2 mm, scan time = 5 min), iEPI and SAP-EPI images (resolution = 0.94 × 0.94 × 2 mm) were acquired in a faster scan time (1:52 min) with twice the brain coverage. SAP-EPI showed motion-correction capability and some immunity to undersampling from rejected data. While 3D SAP-EPI suffers from some geometric distortion, its short scan time and motion-correction capability suggest that SAP-EPI may be a useful alternative to GRE and iEPI for use in SWI, particularly in uncooperative patients. © 2014 Wiley Periodicals, Inc.

  10. ECHO-UseFY17.png | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  11. Watershed Statistics | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  12. X-ray Echo Spectroscopy

    Science.gov (United States)

    Shvyd'ko, Yuri

    2016-02-01

    X-ray echo spectroscopy, a counterpart of neutron spin echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a pointlike x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-0.02 meV ultrahigh-resolution IXS applications (resolving power >108 ) with broadband ≃5 - 13 meV dispersing systems are introduced featuring more than 103 signal enhancement. The technique is general, applicable in different photon frequency domains.

  13. Reestablishing natural succession on acidic mine spoils at high elevations: long-term ecological restoration

    Science.gov (United States)

    Ray W. Brown; Michael C. Amacher; Walter F. Mueggler; Janice Kotuby-Amacher

    2003-01-01

    Methods for restoring native plant communities on acidic mine spoils at high elevations were evaluated in a "demonstration area" in the New World Mining District of southern Montana. Research plots installed in 1976 were assessed for 22 years and compared with adjacent native reference plant communities. A 1.5-acre (0.61-ha) area of mine spoils was shaped and...

  14. Revegetation of Alaskan coal mine spoils. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, W W; Mitchell, G A; McKendrick, J D

    1980-05-23

    Activities initiated after the start of the revegetation project on Alaskan coal mine spoils on September 1, 1979 have consisted mainly of some fall plantings (dormant seedings) and soil and coal spoil samplings and analyses. Because of the late summer start for the project, only a limited amount of field work could be initiated in plant material studies. This consisted of a fall planting at the Usibelli mine site at Healy in interior Alaska. The planting was intended to test the efficacy of seeding in the frost period following the growing season, requiring the seed to remain dormant over winter and to germinate when conditions become favorable in late spring. It also was intended as a comparison of a number of different grasses. Thirty entries were seeded in three replications. Fifteen species of grasses and a clover were included in the trial. The site provided for the trial was on overburden material along a streambed. Among the entries were eight cultivars of introduced grasses, five cultivars of native Alaskan germplasm, one introduced clover cultivar, and sixteen experimental grasses mainly of Alaskan origin.

  15. Vegetational stabilization of uranium spoil areas, grants, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, N.E.

    1979-01-01

    Factors that could be detrimental to vegetative stabilization of uranium mine and mill waste material were examined. Physical and chemical analyses of materials from an open-pit uranium mine and material from three inactive mill tailing piles in New Mexico were performed. Analyses for selected trace elements in mill tailing material and associated vegetation from piles in New Mexico, Colorado, and Utah were also performed. Field and laboratory experiments identified problems associated with establishing vegetation on spoil material. Problems of uptake and concentration of toxic elements by plants growing on specific spoil material were also identified. Ecological observations in conjunction with physical and chemical analyses of specific geologic units, which form the overburden and waste dumps at the open-pit mine, identified a specific geologic material that, if segregated and placed on the surface of the dumps, would pose the least set of problems for a revegetation program. A pilot revegetation project verified that segregation and use of specific geologic material in the overburden could be utilized successfully and economically for reestablishment of native vegetation on mine waste material.

  16. Vegetational stabilization of uranium spoil areas, grants, New Mexico

    International Nuclear Information System (INIS)

    Kelley, N.E.

    1979-01-01

    Factors that could be detrimental to vegetative stabilization of uranium mine and mill waste material were examined. Physical and chemical analyses of materials from an open-pit uranium mine and material from three inactive mill tailing piles in New Mexico were performed. Analyses for selected trace elements in mill tailing material and associated vegetation from piles in New Mexico, Colorado, and Utah were also performed. Field and laboratory experiments identified problems associated with establishing vegetation on spoil material. Problems of uptake and concentration of toxic elements by plants growing on specific spoil material were also identified. Ecological observations in conjunction with physical and chemical analyses of specific geologic units, which form the overburden and waste dumps at the open-pit mine, identified a specific geologic material that, if segregated and placed on the surface of the dumps, would pose the least set of problems for a revegetation program. A pilot revegetation project verified that segregation and use of specific geologic material in the overburden could be utilized successfully and economically for reestablishment of native vegetation on mine waste material

  17. Echo phenomena in a plasma

    International Nuclear Information System (INIS)

    Pavlenko, V.N.

    1983-01-01

    The mechanism of echo phenomenon in different plasma media: laboratory and cosmic plasma, metals and semiconductors is analyzed to get a more comprehensive idea on collective processes in a plasma and for practical applications in radiophysics and plasma diagnostics. The echo phenomenon permitted to confirm a reversible nature of the Landau damping, to prove the fact that the information on perturbation is conserved in a plasma (as non-damping oscillations of the distribution function) even after disappearing of the macroscopic field. The dependence of the diffusion coefficient on the velocity is measured, microturbulences in a plasma are investigated. New ways of the plasma wave conversion are suggested, as well as ''lightning'' of super-critical plasma layers and regions of plasma non-transparency. Prospective advantages of using echo for studying the mechanisms of charged particle interaction with the surface bounding a plasma are revealed

  18. Accumulation of some metals by legumes and their extractability from acid mine spoils. [USA - Alabama

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.W.; Ibeabuchi, I.O.; Sistani, K.R.; Shuford, J.W. (Alabama A M University, Normal, AL (USA). Dept. of Plant and Soil Science)

    A greenhouse study was conducted to investigate the growth (dry matter yield) of selected legume cover crops; phytoaccumulation of metals such as Zn, Mn, Pb, Cu, Ni, and Al; the extractability of heavy metals from three different Alabama acid mine spoils. The spoils were amended based on soil test recommended levels of N, P, K, Ca and Mg prior to plant growth. Metals were extracted by three extractants (Mehlich 1, DTPA, and 0.1 M HCl) and values correlated with their accumulation by the selected legumes. Among the cover crops, kobe lespedeza {ital Lespedeza striata} (Thung.) Hook and Arn, sericea lespedeza {ital Lespedeza cuneata} (Dum.) G. Don, and red clover (Trifolium pratense L.) did not survive the stressful conditions of the spoils. However, cowpea (Vigna unguiculata L.) followed by Bragg' soybean {ital Glycine max} (L.) Merr. generally produced the highest dry matter yield while accumulating the largest quantity of metals, except Al, from spoils. The extractability of most metals from the spoils was generally in the order of: 0.1 MHCl {gt} DTPA. Mehlich 1 did not extract Pb and 0.1 M HCl did not extract Ni, whereas DTPA extracted all the metals in a small amount relative to HCl and Mehlich 1. All the extractants were quite effective in removing plant-available Zn from the spoils. In general, the extractants' ability to predict plant-available metals depended on the crop species, spoil type, and extractant used. 28 refs., 4 tabs.

  19. Selenium transformation in coal mine spoils: Its environmental impact assessment

    Energy Technology Data Exchange (ETDEWEB)

    Harness, J.; Atalay, A.; Koll, K.J.; Zhang, H.; Maggon, D.

    1991-12-31

    The objective of this program was to conduct an environmental impact assessment study for selenium from coal mine spoils. The use of in-situ lysimetry to predict selenium speciation, transformation, and mobility under natural conditions was evaluated. The scope of the study was to construct and test field-scale lysimeter and laboratory mini-column to assess mobility and speciation of selenium in coal mine overburden and soil systems; to conduct soil and groundwater sampling throughout the state of Oklahoma for an overall environmental impact assessment of selenium; and to conduct an in-depth literature review on the solubility, speciation, mobility, and toxicity of selenium from various sources. Groundwater and surface soil samples were also collected from each county in Oklahoma. Data collected from the lysimeter study indicated that selenium in the overburden of the abandoned mine site was mainly found in the selenite form. The amount of selenite found was too low and immobile to be of concern to the environment. The spoil had equilibrated long enough (over 50 years) that most of the soluble forms of selenium have already been lost. Examination of the overburden indicated the presence of pyrite crystals that precipitated over time. The laboratory mini-column study indicated that selenite is quite immobile and remained on the overburden material even after leaching with dilute acid. Data from groundwater samples indicated that based on the current permissible level for selenium in groundwater (0.01 mg Se/L), Oklahoma groundwater is widely contaminated with the element. However, according to the new regulation (0.05 mg Se/L), which is to be promulgated in 1992, only 9 of the 77 counties in the state exceed the limit.

  20. Effects of contaminated dredge spoils on wetland plant communities: A literature review

    Science.gov (United States)

    Stewart, Paul M.; Garza, Eric L.; Butcher, Jason T.; Simon, Thomas P.

    2003-01-01

    Contaminated dredge spoil is a national concern due to its scope and effects on biota, water quality, and the physical environment. This literature review discusses the effects of contaminated dredge spoils on wetland plant communities. Plant communities naturally shift over time with changing environmental conditions. Addition of toxins and nutrients and changes in hydrology may influence plant community structure. The storage and disposal of nutrient and metal contaminated dredge spoils may cause shifts in nearby plant communities. Shifts in species composition and diversity may not be observed for decades after nutrient enrichment, causing any disturbance to remain undetected. Plant community shifts often have great amounts of inertia and are difficult to reverse.

  1. Acoustic echoes reveal room shape.

    Science.gov (United States)

    Dokmanic, Ivan; Parhizkar, Reza; Walther, Andreas; Lu, Yue M; Vetterli, Martin

    2013-07-23

    Imagine that you are blindfolded inside an unknown room. You snap your fingers and listen to the room's response. Can you hear the shape of the room? Some people can do it naturally, but can we design computer algorithms that hear rooms? We show how to compute the shape of a convex polyhedral room from its response to a known sound, recorded by a few microphones. Geometric relationships between the arrival times of echoes enable us to "blindfoldedly" estimate the room geometry. This is achieved by exploiting the properties of Euclidean distance matrices. Furthermore, we show that under mild conditions, first-order echoes provide a unique description of convex polyhedral rooms. Our algorithm starts from the recorded impulse responses and proceeds by learning the correct assignment of echoes to walls. In contrast to earlier methods, the proposed algorithm reconstructs the full 3D geometry of the room from a single sound emission, and with an arbitrary geometry of the microphone array. As long as the microphones can hear the echoes, we can position them as we want. Besides answering a basic question about the inverse problem of room acoustics, our results find applications in areas such as architectural acoustics, indoor localization, virtual reality, and audio forensics.

  2. Plains hydrology and reclamation project: Spoil ground-water chemistry and its impacts on surface water

    Energy Technology Data Exchange (ETDEWEB)

    Trudell, M.R.

    1988-01-01

    Description of the chemical makeup of spoil groundwater at Diplomat and Vesta mines in the Battle River mining area, 200 km southeast of Edmonton within the Lower Horseshoe Canyon coal zone; and at Highvale and Whitewood Mines in the Lake Wabamun mining area, 100 km west of Edmonton within the Ardley coal zone. This report compares the chemical characteristics of the spoil groundwater for each mine to those of the principal premining aquifer that is disrupted by surface mining. The characterization of spoil groundwater chemistry is based on the sampling and analyses of groundwater from piezometers installed in reclaimed areas. Forty-three samples were collected from 23 piezometers at Vesta Mine, and 54 samples were collected from 32 piezometers at Diplomat Mine. At Highvale Mine, 29 samples were collected from 13 piezometers installed in the reclaimed area at Pit 01. Eleven samples were also collected from piezometers installed in spoil at Whitewood Mine to augment a study of that site.

  3. Load Bearing and Deformation Characteristics of Granular Spoils under Unconfined Compressive Loading for Coal Mine Backfill

    Directory of Open Access Journals (Sweden)

    Guodong Li

    2016-01-01

    Full Text Available The load bearing capacity and deformation response of granular spoils under uniaxial compression are numerically and experimentally investigated, aiming to shed light on the performance of back filled waste spoils while controlling ground subsidence after coal extraction. In numerical study, the particles are assembled in PFC commercial code in light of the digitized real shape of spoils with image technique, which is proved to be consistent with the physical test. The results from numerical and laboratory experiments showed that the complete compressive process of spoils tended to have spatial and temporal characteristics. The load-strain curves of investigated specimens could be divided into three stages (stage I, rearranging stage; stage II, breaking stage; stage III, consolidating stage and three zones (I, rearranging zone; II, interlocking zone; III, consolidated zone from outside to inside. During stage I, the load increasing rate of smaller spoils is relatively low, but it increases faster than larger ones in stages II and III. In addition, spoils with Talbot’s gradation are greater than single gradations. The magnitude of the density in consolidated zone is maximum, indicating that it is the main part holding the overlying strata weight.

  4. Identification of ecotype-specific marker genes for categorization of beer-spoiling Lactobacillus brevis.

    Science.gov (United States)

    Behr, Jürgen; Geissler, Andreas J; Preissler, Patrick; Ehrenreich, Armin; Angelov, Angel; Vogel, Rudi F

    2015-10-01

    The tolerance to hop compounds, which is mainly associated with inhibition of bacterial growth in beer, is a multi-factorial trait. Any approaches to predict the physiological differences between beer-spoiling and non-spoiling strains on the basis of a single marker gene are limited. We identified ecotype-specific genes related to the ability to grow in Pilsner beer via comparative genome sequencing. The genome sequences of four different strains of Lactobacillus brevis were compared, including newly established genomes of two highly hop tolerant beer isolates, one strain isolated from faeces and one published genome of a silage isolate. Gene fragments exclusively occurring in beer-spoiling strains as well as sequences only occurring in non-spoiling strains were identified. Comparative genomic arrays were established and hybridized with a set of L. brevis strains, which are characterized by their ability to spoil beer. As result, a set of 33 and 4 oligonucleotide probes could be established specifically detecting beer-spoilers and non-spoilers, respectively. The detection of more than one of these marker sequences according to a genetic barcode enables scoring of L. brevis for their beer-spoiling potential and can thus assist in risk evaluation in brewing industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Laboratory rainfall simulator studies of selected open-cut coal mine overburden spoils from Central Queensland

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K.G.; Loch, R.J.; Aspinall, T.O.; Bell, L.C. [Eros and Hydrology Group, Jabiru, NT (Australia)

    1997-05-01

    Data on the erodibility of overburden spoils resulting from open-cut coal mining are limited. These data are required to derive parameters for erosion prediction models which can be used in the design of re-formed landscapes after mining. In this study, laboratory rainfall simulation data were used to derive CREAMS (Chemicals, Runoff and Erosion from Agricultural Management Systems) interfill erodibility parameters K and n{sub bov} for Central Queensland coal mine overburden spoils. For the spoils studied, K values ranged from 0.0111 to 0.1398 Mg ha h/(ha MJ mm) and n{sub bov} values ranged from 0.0004 to 0.0081. Sediment yield was transport controlled. Results for 1 spoil, South Blackwater Terang, showed that total soil loss increased linearly with slope, and both K and n{sub bov} varied non-linearly with slope. If a constant set of K and n{sub bov} values is used in modelling, CREAMS over-predicts spoil loss for slopes greater than that for which the parameter values were determined, and under-predicts spoil loss for slopes less than that for which the parameter values were determined.

  6. Influences of humic and fulvic acids and organic matter on leachate chemistry from acid coal spoil

    International Nuclear Information System (INIS)

    Gentry, C.E.; Davidson, W.H.; Wade, G.L.

    1994-01-01

    Column-leaching experiments were conducted on an acid pyritic coal spoil to determine the influence of acid rain, humic acid (HA), fulvic acid (FA), and undecomposed organic matter (OM) on pH and Al, Fe, Mn, and SO 4 concentrations in the spoil leachate and on the spoil. Simulated acid rain of pH 4.0 was applied for 50 weeks under laboratory conditions to spoil columns modified with 0.5% FA or HA, or 2.0% OM from four forest trees and two herbs. Quality-control methods were used to evaluate treatment effects. Addition of HA and tall fescue leaf material to a Lily, KY, spoil created a greater and longer lasting desirable effect on leachate pH and Al, Fe, Mn, and SO 4 than additions of FA or OM of five other species. Results suggest that revegetation resulting in rapid production of matured soil OM may reduce the amount of some ions commonly leached from acid mine spoils

  7. Reforestation of Bauxite mine spoils with Eucalyptus tereticornis Sm. seedlings inoculated with Arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    A. Karthikeyan

    2012-12-01

    Full Text Available Open cast mining for bauxite at Yercaud hills (India resulted in degradation of forest ecosystem and production of large quantities of waste rocks (called mine spoils. To ameliorate mine spoils, topsoil is used to spread over before the planting of tree species, conventional method as the topsoil has a good structure, water holding capacity and beneficial microbes like Arbuscular Mycorrhizal (AM fungi essential for plant growth. However, the use of top soil is expensive and in this study bauxite mine spoils were reforestated with AM fungi instead of it. The beneficial microbes AM fungi (Glomus aggregatum Schenck & Smith, G. fasciculatum (Thatcher Gerd. & Trappe emend. Walker & Koske, G. geosporum (Nicol. & Gerd. Walker were isolated, cultured and inoculated into the seedlings ofEucalyptus tereticornis Sm. and grown in bauxite mine spoils as potting medium under nursery conditions. Then, the biomass improved seedlings of E. tereticornis with inoculation of AM fungi were directly transplanted at bauxite mine spoils. After transplantation of the seedlings at bauxite mine spoils, the growth and survival rate were monitored for two years. The AM fungi inoculated seedlings ofE. tereticornis showed 95% survival over the control seedlings and their growth was also significantly higher. Tissue nutrients (N, P, K were also found higher in AM fungi inoculated E. tereticornis than un inoculated control seedlings. 

  8. Reforestation of bauxite mine spoils with Eucalyptus tereticornis Sm. seedlings inoculated with arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    N. Krishnakumar

    2012-11-01

    Full Text Available Open cast mining for bauxite at Yercaud hills (India resulted indegradation of forest ecosystem and production of large quantities of waste rocks (called mine spoils. To ameliorate mine spoils, topsoil is used to spread over before the planting of tree species, conventional method as the topsoil has a good structure, water holding capacity and beneficial microbes like Arbuscular Mycorrhizal (AM fungi essential for plant growth.However, the use of top soil is expensive and in this study bauxite mine spoils were reforestated with AM fungi instead of it. The beneficial microbes AM fungi (Glomus aggregatum Schenck & Smith, G. fasciculatum(Thatcher Gerd. & Trappe emend. Walker & Koske, G. geosporum(Nicol. & Gerd. Walker were isolated, cultured and inoculated into the seedlings of Eucalyptus tereticornis Sm. and grown in bauxite mine spoils as potting medium under nursery conditions. Then, the biomass improved seedlings of E. tereticornis with inoculation of AM fungi were directly transplanted at bauxite mine spoils. After transplantation of the seedlings at bauxite mine spoils, the growth and survival rate were monitored for two years. The AM fungi inoculated seedlings of E. tereticornis showed 95% survival over the control seedlings and their growth was also significantlyhigher. Tissue nutrients (N, P, K were also found higher inAM fungi inoculated E. tereticornis than un inoculated control seedlings.

  9. MR elastography of liver fibrosis: preliminary results comparing spin-echo and echo-planar imaging

    Energy Technology Data Exchange (ETDEWEB)

    Huwart, Laurent; Salameh, Najat; Peeters, Frank; Beers, Bernard E. van [Universite Catholique de Louvain, St-Luc University Hospital, Diagnostic Radiology Unit, Brussels (Belgium); Beek, Leon ter [Philips Medical Systems, Best (Netherlands); Vicaut, Eric [Universite Paris Diderot, Hopital Lariboisiere, Paris (France); Sinkus, Ralph [Universite Paris Diderot, Laboratoire Ondes et Acoustique, Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris, Paris (France)

    2008-11-15

    The purpose of this study was to prospectively compare the performance of magnetic resonance (MR) elastography using echo-planar and spin-echo imaging for staging of hepatic fibrosis. Twenty-four patients who had liver biopsy for suspicion of chronic liver disease had MR elastography performed with both spin-echo and echo-planar sequences. At histology, the fibrosis stage was assessed according to METAVIR. The data acquisition time was about 20 min using spin-echo, and only 2 min using echo-planar imaging. The hepatic signal-to-noise ratios were similar on both images (22.51 {+-} 5.37 for spin-echo versus 21.02 {+-} 4.76 for echo-planar, p = 0.33). The elasticity measurements and the fibrosis stages were strongly correlated. The Spearman correlation coefficients were r = 0.91 (p < 0.01) with spin-echo and r = 0.84 (p < 0.01) with echo-planar sequences. These correlation coefficients did not differ significantly (p = 0.17). A strong correlation was also observed between spin-echo and echo-planar elasticity (r = 0.83, p < 0.001), without systematic bias. The results of our study showed that echo-planar imaging substantially decreased the data acquisition time of MR elastography, while maintaining the image quality and diagnostic performance for staging of liver fibrosis. This suggests that echo-planar MR elastography could replace spin-echo MR elastography in clinical practice. (orig.)

  10. Nonlinear theory of transverse beam echoes

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Tanaji; Li, Yuan Shen

    2017-10-04

    Transverse beam echoes can be excited with a single dipole kick followed by a single quadrupole kick. They have been used to measure diffusion in hadron beams and have other diagnostic capabilities. Here we develop theories of the transverse echo nonlinear in both the dipole and quadrupole kick strengths. The theories predict the maximum echo amplitudes and the optimum strength parameters. We find that the echo amplitude increases with smaller beam emittance and the asymptotic echo amplitude can exceed half the initial dipole kick amplitude. We show that multiple echoes can be observed provided the dipole kick is large enough. The spectrum of the echo pulse can be used to determine the nonlinear detuning parameter with small amplitude dipole kicks. Simulations are performed to check the theoretical predictions. In the useful ranges of dipole and quadrupole strengths, they are shown to be in reasonable agreement.

  11. Longitudinal collective echoes in coasting particle beams

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Khateeb

    2003-01-01

    Full Text Available Longitudinal ballistic and collective beam echoes with diffusion effects are investigated theoretically. In the presence of the space-charge impedance, the collective echo amplitude is obtained as a closed form expression. In contrast to the ballistic case, the collective echo amplitude consists of one maximum at time t_{echo}. The echo amplitude grows up and damps down with a rate proportional to the Landau damping rate of space-charge waves. The effect of weak diffusion is found to modify the ballistic and the collective echo amplitudes in the same manner. This effect of diffusion was confirmed using a “noiseless,” grid-based simulation code. As a first application the amount of numerical diffusion in our simulation code was determined using the echo effect.

  12. Echo-Enabled Harmonic Generation

    Energy Technology Data Exchange (ETDEWEB)

    Stupakov, Gennady; /SLAC

    2012-06-28

    A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demonstration of the EEHG.

  13. Acetobacter oeni sp. nov., isolated from spoiled red wine.

    Science.gov (United States)

    Silva, Luis R; Cleenwerck, Ilse; Rivas, Raúl; Swings, Jean; Trujillo, Martha E; Willems, Anne; Velázquez, Encarna

    2006-01-01

    A bacterial strain, designated B13T, was isolated from spoiled red wine from the Dão region, Portugal. The strain was Gram-negative, strictly aerobic, rod-shaped and motile. Phylogenetic analysis on the basis of 16S rRNA gene sequences indicated that B13T belonged to the genus Acetobacter within the Alphaproteobacteria. The closest related species was Acetobacter aceti, with 98.4 % 16S rRNA gene sequence similarity. DNA-DNA hybridization showed that B13T constituted a taxon separate from the Acetobacter species with validly published names. The DNA G+C content of B13T was 58.1 mol%. Phenotypic characteristics of B13T allowed its differentiation from the recognized Acetobacter species. B13T produced 5-ketogluconic acid from glucose, but no 2-ketogluconic acid. It produced catalase, but no oxidase. It utilized glycerol, but not maltose, ethanol or methanol as carbon sources. On the basis of the results obtained, B13T represents a novel species for which the name Acetobacter oeni sp. nov. is proposed. The type strain is B13T (= LMG 21952T = CECT 5830T).

  14. Merits of partial shielding in dumping sediment spoils.

    Science.gov (United States)

    Jensen, Jacob Hjelmager; Saremi, Sina; Jimenez, Carlos; Hadjioannou, Louis

    2015-12-15

    The commonly adopted method of dumping dredge spoil at sea using split-hull barges leads to considerable sediment loss to the water column and a subsequent dispersion of fine material that can pose a risk to sensitive "downstream" habitats such as coral reefs. Containing sediment loads using stitched closed geotextile bags is practiced for minimizing loss of contaminated sediment, but is expensive in terms of operational efficiency. Following promising observations from initial laboratory trials, the plunging of partially shielded sediment loads, released on open sea, was studied. The partial shielding was achieved with rigid, open containers as well as flexible, open bags. The loss of sediment from these modes of shielding was measured, and it was observed that even limited and unstitched shielding can be effective in debilitating the entrainment of water into the descending load. In particular, long-sleeved flexible bags practically self-eliminated the exposure of the load and thus losses. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Independence of echo-threshold and echo-delay in the barn owl.

    Directory of Open Access Journals (Sweden)

    Brian S Nelson

    Full Text Available Despite their prevalence in nature, echoes are not perceived as events separate from the sounds arriving directly from an active source, until the echo's delay is long. We measured the head-saccades of barn owls and the responses of neurons in their auditory space-maps while presenting a long duration noise-burst and a simulated echo. Under this paradigm, there were two possible stimulus segments that could potentially signal the location of the echo. One was at the onset of the echo; the other, after the offset of the direct (leading sound, when only the echo was present. By lengthening the echo's duration, independently of its delay, spikes and saccades were evoked by the source of the echo even at delays that normally evoked saccades to only the direct source. An echo's location thus appears to be signaled by the neural response evoked after the offset of the direct sound.

  16. Beam echoes in the presence of coupling

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Axel [Case Western Reserve U.

    2017-10-03

    Transverse beam echoes could provide a new technique of measuring diusion characteristics orders of magnitude faster than the current methods; however, their interaction with many accelerator parameters is poorly understood. Using a program written in C, we explored the relationship between coupling and echo strength. We found that echoes could be generated in both dimensions, even with a dipole kick in only one dimension. We found that the echo eects are not destroyed even when there is strong coupling, falling o only at extremely high coupling values. We found that at intermediate values of skew quadrupole strength, the decoherence time of the beam is greatly increased, causing a destruction of the echo eects. We found that this is caused by a narrowing of the tune width of the particles. Results from this study will help to provide recommendations to IOTA (Integrable Optics Test Accelerator) for their upcoming echo experiment.

  17. Lactobacillus cerevisiae sp. nov., isolated from a spoiled brewery sample.

    Science.gov (United States)

    Koob, Jennifer; Jacob, Fritz; Wenning, Mareike; Hutzler, Mathias

    2017-09-01

    A Gram-stain-positive, non-motile, rod-shaped bacterium, designated TUM BP 140423000-2250T (=DSM 100836T=LMG 29073T), was isolated from spoiled beer. This bacterium did not form spores, and was catalase-negative and facultatively anaerobic. Its taxonomic position was determined in a polyphasic study. The 16S rRNA gene sequence similarity data showed that the strain belonged to the Lactobacillus genus with the nearest neighbours being Lactobacillus koreensis DCY50T (sequence similarity 99.5 %), Lactobacillus yonginensis THK-V8T (99.2 %) and Lactobacillus parabrevis LMG 11984T (98.7 %). Sequence comparisons of additional phylogenetic markers, pheS and rpoA, confirmed the 16S rRNA gene sequence tree topology. The maximum rpoA sequence similarity was 92.3 % with L. yonginensis THK-V8T. The DNA G+C content of the isolate was 50.0 mol%. The DNA-DNA relatedness showed that strain TUM BP 140423000-2250T could be clearly distinguished from L. koreensis DCY 50T (30.8±0.4 %) and L. yonginensis THK-V8T (23.6±5.9 %). The major fatty acids were C18 : 1ω9c, summed feature 7 (comprised of C19 : 0 cyclo ω10c/C19 : 1ω6c) and C16 : 0. Based on phenotypic and genotypic studies, the authors propose classifying the new isolate as a representative of a novel species of the genus Lactobacillus, Lactobacillus cerevisiae sp. nov. The type strain is deposited at the Research Centre Weihenstephan for Brewing and Food Quality as TUM BP 140423000-2250T (=DSM 100836T=LMG 29073T).

  18. Vetiver Grass: a potential tool for phytoremediation of iron ore mine site spoil dump

    Directory of Open Access Journals (Sweden)

    Anita Mukherjee

    2015-06-01

    Full Text Available The impact of mining has lead to the generation of a large amount of spoil dumps that has become dangerous to human health, wildlife and biodiversity. Thus it is essential that the post mining areas and waste land generated need to be rapidly vegetated. Vetiver grass (Chrysopogon zizanioides (L. Roberty is a tropical plant which grows naturally in various soil conditions and is well known for its ability to resist DNA damage while growing on typically polluted soil conditions. The spoil dumps from the iron mine site is unstable and inhospitable for plant growth due to presence of various toxic heavy metals like - Fe, Mn, Zn, Cu, Pb, Ni, Cr, Cd etc. Vetiver system is an efficient bio-engineering tool for reclaiming such spoil dumps. There are 12 known species of Vetiver grass, and many hundreds of different cultivars that are exploited by users depending on need. In the present study we selected the polyploid infertile variety of vetiver and carried pot experiments. Vetiver plants grown on the iron ore mine spoil dump show distinct differences in their growth with fewer numbers of tillers, reduced chlorophyll content, upregulation of antioxidant enzymes and increased proline content. To investigate the level of DNA damage incurred and change in the genetic stability Comet assay and RAPD analysis were performed. Results confirmed that Vetiver grass can serve as a model species for phytoremediating the iron ore mine spoil dumps.

  19. Establishment of native species on amended and unamended coal mine spoil in central Queensland

    International Nuclear Information System (INIS)

    Bell, L.C.; Mulligan, D.R.; Orr, M.S.; Johnstone, P.

    1994-01-01

    At the Curragh open-cut coal mine in central Queensland, tree and shrub growth on amended and unamended spoil was assessed over a 5-year period. The most successful media in terms of seedling densities were bare spoil and spoil covered by a thin layer of coarse coal reject. Where soil was replaced, very few native species established due to the intense competition from exotic grasses. Given this poor establishment on soil, the question of how well an ecosystem would develop on non-soil media was addressed by assessing the ability of each of the media to support sustainable communities in the longer term. Early results from direct-seeding tree and shrub species onto non-soil media have been quite encouraging, but analysis of the surface horizons has shown that after several years, there are still some characteristics which could either limit the re-establishment, and/or prevent the sustainability, of new communities. Due primarily to the high sulfate levels originally in the coal reject, the surface salinity in these treatments was much higher than in the uncapped spoil. Substrate analyses have shown also that there was a much lower concentration of mineralizable N in the spoil and coal reject than in the soil, revealing that the potential of these non-soil substrates to continue supplying nitrogen to the system is greatly reduced. Furthermore, the concentration of microbial biomass carbon was significantly lower in these media, and the percentage ground cover after 5 years was generally <10%

  20. Multiple echo multi-shot diffusion sequence.

    Science.gov (United States)

    Chabert, Steren; Galindo, César; Tejos, Cristian; Uribe, Sergio A

    2014-04-01

    To measure both transversal relaxation time (T2 ) and diffusion coefficients within a single scan using a multi-shot approach. Both measurements have drawn interest in many applications, especially in skeletal muscle studies, which have short T2 values. Multiple echo single-shot schemes have been proposed to obtain those variables simultaneously within a single scan, resulting in a reduction of the scanning time. However, one problem with those approaches is the associated long echo read-out. Consequently, the minimum achievable echo time tends to be long, limiting the application of these sequences to tissues with relatively long T2 . To address this problem, we propose to extend the multi-echo sequences using a multi-shot approach, so that to allow shorter echo times. A multi-shot dual-echo EPI sequence with diffusion gradients and echo navigators was modified to include independent diffusion gradients in any of the two echoes. The multi-shot approach allows us to drastically reduce echo times. Results showed a good agreement for the T2 and mean diffusivity measurements with gold standard sequences in phantoms and in vivo data of calf muscles from healthy volunteers. A fast and accurate method is proposed to measure T2 and diffusion coefficients simultaneously, tested in vitro and in healthy volunteers. Copyright © 2013 Wiley Periodicals, Inc.

  1. Rapid MR imaging of the liver. Comparison of twelve techniques for single breath-hold whole volume acquisition

    International Nuclear Information System (INIS)

    Naganawa, Shinji; Jenner, Goeran; Cooper, T.G.; Potchen, E.J.; Ishigaki, Takeo

    1994-01-01

    Twelve magnetic resonance imaging pulse sequences for single breath-hold whole volume acquisition of the liver were evaluated on volunteers. Liver and spleen contrast to noise ratio (C/N), overall image quality, and grade of artifacts were compared. The 12 sequences included T 2 -weighted fast spin echo (FSE) with or without fat suppression (FS), fast multiplanar spoiled gradient recalled imaging (FMPSPGR), fast gradient recalled imaging without preparation pulses (FGR), FGR with inversion recovery preparation pulse nulling the liver or fat (IR-FGR-L and IR-FGR-F), FGR with driven equilibrium preparation pulse (DE-FGR), single shot moderately or heavily T 2 -weighted spin echo echo planar imaging (SE-EPI-mT2 and SE-EPI-hT2), multi-shot moderately T 2 -weighted spin echo echo planar imaging (multi-shot SE-EPI-mT2), inversion recovery EPI, and gradient echo EPI. In the quantitative analysis, FSE + FS showed a significantly higher C/N ratio than the others (p<0.05). In the qualitative evaluation, DE-prepFGR, and single and multi-shot SE-EPI-mT2 had good results, as did FSE and FSE + FS. Further studies should be conducted to determine whether or not these breath-hold sequences can obviate current conventional non-breath-hold sequences. (author)

  2. How to misuse echo contrast

    Directory of Open Access Journals (Sweden)

    Missios Anna

    2009-01-01

    Full Text Available Abstract Background Primary intracardiac tumours are rare, there are however several entities that can mimic tumours. Contrast echocardiography has been suggested to aid the differentiation of various suspected masses. We present a case where transthoracic echocardiography completely misdiagnosed a left atrial mass, partly due to use of echo contrast. Case presentation An 80 year-old woman was referred for transthoracic echocardiography because of one-month duration of worsening of dyspnoea. Transthoracic echocardiography displayed a large echodense mass in the left atrium. Intravenous injection of contrast (SonoVue, Bracco Inc., It indicated contrast-enhancement of the structure, suggesting tumour. Transesophageal echocardiography revealed, however, a completely normal finding in the left atrium. Subsequent gastroscopy examination showed a hiatal hernia. Conclusion It is noteworthy that the transthoracic echocardiographic exam completely misdiagnosed what seemed like a left atrial mass, which in part was an effect of the use of echo contrast. This example highlights that liberal use of transoesophageal echocardiography is often warranted if optimal display of cardiac structures is desired.

  3. A controlled ac Stark echo for quantum memories

    OpenAIRE

    Ham, Byoung S.

    2017-01-01

    A quantum memory protocol of controlled ac Stark echoes (CASE) based on a double rephasing photon echo scheme via controlled Rabi flopping is proposed. The double rephasing scheme of photon echoes inherently satisfies the no-population inversion requirement for quantum memories, but the resultant absorptive echo remains a fundamental problem. Herein, it is reported that the first echo in the double rephasing scheme can be dynamically controlled so that it does not affect the second echo, whic...

  4. Does the sequence of plant dominants affect mycorrhiza development in simulated succession on spoil banks?

    Czech Academy of Sciences Publication Activity Database

    Püschel, David; Rydlová, Jana; Vosátka, Miroslav

    2008-01-01

    Roč. 302, 1-2 (2008), s. 273-282 ISSN 0032-079X R&D Projects: GA MŠk(CZ) 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : arbuscular mycorrhizal fungi * plant succession * spoil banks Subject RIV: EF - Botanics Impact factor: 1.998, year: 2008

  5. Forest-biological erosion control on coal-mine spoil banks in Bulgaria

    International Nuclear Information System (INIS)

    Haigh, M.J.; Gentcheva-Kostadinova, S.; Zheleva, E.

    1995-01-01

    The forest fallowing of coal-mine spoils helps re-establish the processes of natural, self-sustaining, soil formation. Environmental monitoring in Bulgaria demonstrates that forestation can moderate soil pH (from ph> 3.0 to pH 1.3 g/cm 3 in the 0-5 cm layer) in the case of coal briquette spoils at Pernik, near Sofia. Ground losses from forested, 16-17 degree slope, coal briquette-spoils at Pernik are a quarter of those from an entirely unvegetated section of the same embankment (48.5 vs 12. 1 mm in the period 1988-1994) despite the absence of ground cover beneath the trees. On lignite spoil banks, at Maritsa-Iztok, central Bulgaria, forestation increases the organic content of the soil to greater depths than revegetation with grass, and to a greater degree than conventional agricultural cultivation. On Pinus nigra forested crest sites at Pernik, and in Robinia pseudacacia forested groves on the lignite minespoil banks at Maritsa-Iztok, slopes showed ground advance rather than ground retreat. Slopes protected by mechanical means alone did not allow soil growth and, where the structure broke down, they suffered as much erosion as untreated sites. In sum, the forest fallowing of surface coal-mine disturbed land accelerates organic matter accumulation in the soil, helps improve soil structure, reduces erosion, and may transform soil loss into soil gain, even on steeply sloping sites. 17 refs., 3 figs., 1 tab

  6. Earthworm succession in afforested colliery spoil heaps in the Sokolov region, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Pižl, Václav

    2001-01-01

    Roč. 9, č. 4 (2001), s. 359-364 ISSN 1061-2971 Institutional research plan: CEZ:AV0Z6066911 Keywords : earthworms * colliery spoil heaps * succession Subject RIV: EH - Ecology, Behaviour Impact factor: 1.011, year: 2001

  7. Photobacterium piscicola sp. nov., isolated from marine fish and spoiled packed cod

    NARCIS (Netherlands)

    Figge, Marian; Cleenwerck, Ilse; van Uijen, Astrid; de Vos, Paul; Huys, Geert; Robertson, Lesley

    Five isolates from marine fish (W3T, WM, W1S, S2 and S3) and three isolates misclassified as Photobacterium phosphoreum, originating from spoiled modified atmosphere packed stored cod (NCIMB 13482 and NCIMB 13483) and the intestine of skate (NCIMB 192), were subjected to a polyphasic taxonomic

  8. 30 CFR 817.71 - Disposal of excess spoil: General requirements.

    Science.gov (United States)

    2010-07-01

    ... stable under all conditions of construction. (c) Compliance with permit. You, the permittee or operator... (excavations to stable bedrock) or rock-toe buttresses to ensure fill stability. (e) Placement of excess spoil... provided to minimize surface erosion at the site. All disturbed areas, including diversion channels that...

  9. 30 CFR 816.71 - Disposal of excess spoil: General requirements.

    Science.gov (United States)

    2010-07-01

    ... stable under all conditions of construction. (c) Compliance with permit. You, the permittee or operator... (excavations to stable bedrock) or rock-toe buttresses to ensure fill stability. (e) Placement of excess spoil... provided to minimize surface erosion at the site. All disturbed areas, including diversion channels that...

  10. Soil quality and carbon sequestration in a reclaimed coal mine spoil of Jharia coalfield, India

    Science.gov (United States)

    Mukhopadhyay, Sangeeta; Masto, Reginald; Ram, Lal

    2016-04-01

    Revegetation of coal mine spoil helps in carbon storage and the success of remediation depend on the selection of appropriate tree species. A study was conducted at the coalmine overburden dumps of Jharia Coalfield, Dhanbad, India to evaluate the impact of revegetation on the overall soil quality and carbon sequestration. Morphological parameters (tree height, diameter at breast height, tree biomass, wood specific gravity) of the dominant tree species (Acacia auriculiformis, Cassia siamea, Dalbergia sissoo and Leucaena leucocephala) growing on the mine spoil was recorded. Mine spoil samples were collected under the canopy cover of different tree species and analyzed for soil physical, chemical, and biological parameters. In general reclaimed sites had better soil quality than the reference site. For instance, D. sissoo and C. siamea improved soil pH (+28.5%, +27.9%), EC (+15.65%, +19%), cation exchange capacity (+58.7%, +52.3%), organic carbon (+67.5%, +79.5%), N (+97.2%, +75.7%), P (+98.2%, +76.9%), K (+31.8%, +37.4%), microbial biomass carbon (+143%, +164%) and dehydrogenase activity (+228%, +262%) as compared to the unreclaimed reference coal mine site. The concentration of polycyclic aromatic hydrocarbons (PAHs) decreased significantly in the reclaimed site than the reference spoil, C. siamea was found to be more promising for PAH degradation. The overall impact of tree species on the quality of reclaimed mine spoil cannot be assessed by individual soil parameters, as most of the parameters are interlinked and difficult to interpret. However, combination of soil properties into an integrated soil quality index provides a more meaningful assessment of reclamation potential of tree species. Principal component analysis (PCA) was used to identify key mine soil quality indicators to develop a soil quality index (SQI). Coarse fraction, pH, EC, soil organic carbon, P, Ca, S, and dehydrogenase activity were the most critical properties controlling growth of tree

  11. T2{sup *} mapping from multi-echo dixon sequence on gadoxetic acid-enhanced magnetic resonance imaging for the hepatic fat quantification: Can it be used for hepatic function assessment?

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hyun Suk; Lee, Jeong Min; Yoon, Jeong Hee; Kang, Hyo Jin; Lee, Sang Min; Yang, Hyun Kyung; Han, Joon Koo [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-08-01

    To evaluate the diagnostic value of T2{sup *} mapping using 3D multi-echo Dixon gradient echo acquisition on gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) as a tool to evaluate hepatic function. This retrospective study was approved by the IRB and the requirement of informed consent was waived. 242 patients who underwent liver MRIs, including 3D multi-echo Dixon fast gradient-recalled echo (GRE) sequence at 3T, before and after administration of gadoxetic acid, were included. Based on clinico-laboratory manifestation, the patients were classified as having normal liver function (NLF, n = 50), mild liver damage (MLD, n = 143), or severe liver damage (SLD, n = 30). The 3D multi-echo Dixon GRE sequence was obtained before, and 10 minutes after, gadoxetic acid administration. Pre- and post-contrast T2{sup *} values, as well as T2{sup *} reduction rates, were measured from T2{sup *} maps, and compared among the three groups. There was a significant difference in T2{sup *} reduction rates between the NLF and SLD groups (−0.2 ± 4.9% vs. 5.0 ± 6.9%, p = 0.002), and between the MLD and SLD groups (3.2 ± 6.0% vs. 5.0 ± 6.9%, p = 0.003). However, there was no significant difference in both the pre- and post-contrast T2{sup *} values among different liver function groups (p = 0.735 and 0.131, respectively). A receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve for using T2{sup *} reduction rates to differentiate the SLD group from the NLF group was 0.74 (95% confidence interval: 0.63–0.83). Incorporation of T2{sup *} mapping using 3D multi-echo Dixon GRE sequence in gadoxetic acid-enhanced liver MRI protocol may provide supplemental information for liver function deterioration in patients with SLD.

  12. Gravitational wave sources: reflections and echoes

    Science.gov (United States)

    Price, Richard H.; Khanna, Gaurav

    2017-11-01

    The recent detection of gravitational waves has generated interest in alternatives to the black hole interpretation of sources. A subset of such alternatives involves a prediction of gravitational wave ‘echoes’. We consider two aspects of possible echoes: first, general features of echoes coming from spacetime reflecting conditions. We find that the detailed nature of such echoes does not bear any clear relationship to quasi-normal frequencies. Second, we point out the pitfalls in the analysis of local reflecting ‘walls’ near the horizon of rapidly rotating black holes.

  13. Gravitational wave sources: reflections and echoes

    International Nuclear Information System (INIS)

    Price, Richard H; Khanna, Gaurav

    2017-01-01

    The recent detection of gravitational waves has generated interest in alternatives to the black hole interpretation of sources. A subset of such alternatives involves a prediction of gravitational wave ‘echoes’. We consider two aspects of possible echoes: first, general features of echoes coming from spacetime reflecting conditions. We find that the detailed nature of such echoes does not bear any clear relationship to quasi-normal frequencies. Second, we point out the pitfalls in the analysis of local reflecting ‘walls’ near the horizon of rapidly rotating black holes. (paper)

  14. Cooperative broadband spin echoes through optimal control

    Science.gov (United States)

    Kallies, Wolfgang; Glaser, Steffen J.

    2018-01-01

    The Hahn echo sequence is one of the most common building blocks in magnetic resonance, consisting of an excitation pulse and a refocusing pulse. Conventional approaches to improve the performance of echo experiments focused on the optimization of individual pulses, compensating their own imperfections. Here we present an approach to concurrently design both pulses such that they also compensate each others imperfections. The fact that for such cooperative pulses the individual pulses do not need to be perfect provides additional degrees of freedom, resulting in improved overall Hahn echo performance. Single-scan cooperative pulses are compared to conventional approaches by simulations as well as experiments.

  15. Sparse adaptive filters for echo cancellation

    CERN Document Server

    Paleologu, Constantin

    2011-01-01

    Adaptive filters with a large number of coefficients are usually involved in both network and acoustic echo cancellation. Consequently, it is important to improve the convergence rate and tracking of the conventional algorithms used for these applications. This can be achieved by exploiting the sparseness character of the echo paths. Identification of sparse impulse responses was addressed mainly in the last decade with the development of the so-called ``proportionate''-type algorithms. The goal of this book is to present the most important sparse adaptive filters developed for echo cancellati

  16. Solid speciation and availability of nickel and chromium in Ni mining spoils

    Science.gov (United States)

    Raous, Sophie; Garnier, Jérémie; Sterckeman, Thibaul; Echevarria, Guillaume; Becquer, Thierry; Thomas, Fabien

    2010-05-01

    Nickel mining of ultramafic laterites generates different types of wastes, topsoils and ores that are too poor in Ni to be currently processed. These are mixed and stored on heaps which could be a potential source of Ni and Cr pollution. Chemical reactivity of the main metal bearing phases present in the mining spoils of Goiás (Brasil) was investigated. Principally a silicated 'saprolite' material and a Fe-oxide rich limonitic material were isolated from the wastes. Their total Ni and Cr content are high, respectively for Ni and Cr : 7,170 and 54,970 mg kg-1 in limonite and 12,200 and 12,650 mg kg-1 in saprolite. The main metal-bearing minerals, identified and localized using XRD, TEM-EDX, Raman spectroscopy and Mossbaüer spectrometry are well-crystallized minerals: goethite (75%), hematite (13%) and chromite in limonite and ferruginous smectite, talc and chromite in saprolite. Single and sequential extractions showed that the amounts of 1M KCl exchangeable Ni and Cr reached respectively 7.1% and 0.03% of total contents in saprolite. Moreover, Cr(VI) extraction by KH2PO4 showed that more than 2% (980 mg kg-1) of total Cr was under this labile toxic form in limonite. This study allowed us to determine the main reactions controlling the Ni and Cr mobility in the spoils i.e. Ni2+ cationic exchange in saprolitic spoil and CrO32- surface complexation in limonitic spoil. This study allowed us to demonstrate the need of chemical rehabilitation of mining wastes in order to avoid the dispersion of the high contents of Ni and Cr available. It constitutes the system definition needed to predict the Cr and Ni mobility in ultramafic mining spoils.

  17. Improving surface stability of elevated spoil landforms using natural landform analogy and geological information

    Science.gov (United States)

    Emmerton, Bevan; Burgess, Jon; Esterle, Joan; Erskine, Peter; Baumgartl, Thomas

    2017-04-01

    Large-scale open cut mining in the Bowen Basin, Queensland, Australia has undergone an evolutionary process over the period of a few decades, transitioning from shallow mining depths, limited spoil elevation and pasture based rehabilitation to increased mining depths, escalating pre-stripping, elevated mesa-like landforms and native woody species rehabilitation. As a consequence of this development, the stabilisation of recent constructed landforms has to be assured through means other than the establishment of vegetative cover. Recent developments are the specific selection and partitioning of resilient fragmental spoil types for the construction of final landform surface. They can also be used as cladding resources for stabilizing steep erosive batters and this has been identified as a practical methodology that has the potential to significantly improve rehabilitation outcomes. Examples of improvements are an increase of the surface rock cover, roughness and infiltration and reducing inherent erodibility and runoff and velocity of surface flow. However, a thorough understanding of the properties and behavior of individual spoil materials disturbed during mining is required. Relevant information from published literature on the geological origins, lithology and weathering characteristics of individual strata within the Bowen Basin Coal Measures located in Queensland, Australia (and younger overlying weathered strata) has been studied, and related both to natural landforms and to the surface stability of major strata types when disturbed by mining. The resulting spoil classification developed from this study is based primarily on inherent geological characteristics and weathering behaviour of identifiable lithologic components, and as such describes the expected fragmental resilience likely within disturbed materials at Bowen Basin coal mines. The proposed classification system allows the allocation of spoil types to use categories which have application in pre

  18. Survival and growth of wildlife shrubs and trees on acid mine spoil

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, D.K.; Adkisson, L.F.

    1980-01-01

    The purpose of this study was to assess the survival and growth of selected wildlife plants over a wide range of acid mine spoil conditions and to identify species suitable for surface mine reclamation. A major criterion in selection of study sites was inclusion of a wide range of spoil acidity conditions. The Ollis Creek (Study Area A) and Farrell (Study Area B) coal surface mines located in Campbell and Scott Counties, Tennessee, were selected for study. Seven plant species, all of which had been used in past reclamation demonstrations, were introduced on the 22 plots during March 1972. Autumn olive (Elaeagnus umbellata) was included as a control plant. Ten additional plant species were introduced during March 1973. With the exception of highbush blueberry (Vaccinium corymbosum var.). European filbert (Corylus avellana), and red maple (Acer rubrum), these species had not been used in TVA reclamation demonstrations. To assess the effects of spoil pH on the plants, the plots were grouped into seven pH categories, and mean percent survival and growth for each species were calculated. Results indicate that autumn olive, elaeagnus cherry, arnot locust, sawtooth oak, red maple, and Toringo crabapple are suitable for quick improvement of surface mine habitat over a wide range of spoil acidity in the Appalachian coalfield. Bessey cherry and European filbert need further study before a decision can be made regarding their reclamation utility. Species that are not recommended for quick habitat improvement over a wide range of surface mine spoil pH conditions include bush honeysuckle, barberry, Siberian crabapple, Manchu cherry, American beautyberry, bear oak, blueberry, rem-red honeysuckle, and redcedar.

  19. Geochemical assessments and classification of coal mine spoils for better understanding of potential salinity issues at closure.

    Science.gov (United States)

    Park, Jin Hee; Li, Xiaofang; Edraki, Mansour; Baumgartl, Thomas; Kirsch, Bernie

    2013-06-01

    Coal mining wastes in the form of spoils, rejects and tailings deposited on a mine lease can cause various environmental issues including contamination by toxic metals, acid mine drainage and salinity. Dissolution of salt from saline mine spoil, in particular, during rainfall events may result in local or regional dispersion of salts through leaching or in the accumulation of dissolved salts in soil pore water and inhibition of plant growth. The salinity in coal mine environments is from the geogenic salt accumulations and weathering of spoils upon surface exposure. The salts are mainly sulfates and chlorides of calcium, magnesium and sodium. The objective of the research is to investigate and assess the source and mobility of salts and trace elements in various spoil types, thereby predicting the leaching behavior of the salts and trace elements from spoils which have similar geochemical properties. X-ray diffraction analysis, total digestion, sequential extraction and column experiments were conducted to achieve the objectives. Sodium and chloride concentrations best represented salinity of the spoils, which might originate from halite. Electrical conductivity, sodium and chloride concentrations in the leachate decreased sharply with increasing leaching cycles. Leaching of trace elements was not significant in the studied area. Geochemical classification of spoil/waste defined for rehabilitation purposes was useful to predict potential salinity, which corresponded with the classification from cluster analysis based on leaching data of major elements. Certain spoil groups showed high potential salinity by releasing high sodium and chloride concentrations. Therefore, the leaching characteristics of sites having saline susceptible spoils require monitoring, and suitable remediation technologies have to be applied.

  20. Echoes in correlated neural systems

    International Nuclear Information System (INIS)

    Helias, M; Tetzlaff, T; Diesmann, M

    2013-01-01

    Correlations are employed in modern physics to explain microscopic and macroscopic phenomena, like the fractional quantum Hall effect and the Mott insulator state in high temperature superconductors and ultracold atoms. Simultaneously probed neurons in the intact brain reveal correlations between their activity, an important measure to study information processing in the brain that also influences the macroscopic signals of neural activity, like the electroencephalogram (EEG). Networks of spiking neurons differ from most physical systems: the interaction between elements is directed, time delayed, mediated by short pulses and each neuron receives events from thousands of neurons. Even the stationary state of the network cannot be described by equilibrium statistical mechanics. Here we develop a quantitative theory of pairwise correlations in finite-sized random networks of spiking neurons. We derive explicit analytic expressions for the population-averaged cross correlation functions. Our theory explains why the intuitive mean field description fails, how the echo of single action potentials causes an apparent lag of inhibition with respect to excitation and how the size of the network can be scaled while maintaining its dynamical state. Finally, we derive a new criterion for the emergence of collective oscillations from the spectrum of the time-evolution propagator. (paper)

  1. Water Dashboard Help | ECHO | US EPA

    Science.gov (United States)

    The dashboards on the ECHO website are specialized to track both facility and agency performance as they relate to compliance with and enforcement of environmental standards under the Clean Water Act (CWA).

  2. Time Delay Estimation Algoritms for Echo Cancellation

    Directory of Open Access Journals (Sweden)

    Kirill Sakhnov

    2011-01-01

    Full Text Available The following case study describes how to eliminate echo in a VoIP network using delay estimation algorithms. It is known that echo with long transmission delays becomes more noticeable to users. Thus, time delay estimation, as a part of echo cancellation, is an important topic during transmission of voice signals over packetswitching telecommunication systems. An echo delay problem associated with IP-based transport networks is discussed in the following text. The paper introduces the comparative study of time delay estimation algorithm, used for estimation of the true time delay between two speech signals. Experimental results of MATLab simulations that describe the performance of several methods based on cross-correlation, normalized crosscorrelation and generalized cross-correlation are also presented in the paper.

  3. Data processing of records of meteoric echoes

    Science.gov (United States)

    Dolinský, P.

    2016-01-01

    The data obtained in the period from 4 November 2014 to 31 July 2014 by our receiving and recording system was statistically processed. The system records meteoric echoes from the TV transmitter Lviv 49.739583 MHz (N49.8480° E24.0369°, Ukraine) using a 4-element Yagi antenna with horizontal polarization (elevation of 0° and azimuth of 60°), receiver ICOM R-75 in the CW mode, and a computer with a recording using HROFFT v1.0.0f. The main goal was to identify weak showers in these data. Mayor or strong showers are visible without processing (referred at IMC2015, Mistelbach). To find or to identify weaker showers is more difficult. Not all echoes are meteoric echoes, but also ionospheric echoes or lightning disturbances are present.

  4. Enforcement and Compliance History Online (ECHO) Facilities

    Data.gov (United States)

    U.S. Environmental Protection Agency — ECHO provides integrated compliance and enforcement information for about 800,000 regulated facilities nationwide. Its features range from simple to advanced,...

  5. TRISP: Three axes spin echo spectrometer

    Directory of Open Access Journals (Sweden)

    Thomas Keller

    2015-12-01

    Full Text Available TRISP, operated by the Max-Planck-Institute for Solid State Research, is a high-resolution neutron spectrometer combining the three axes and neutron resonance spin echo (NRSE techniques.

  6. Echoes of Kerr-like wormholes

    Science.gov (United States)

    Bueno, Pablo; Cano, Pablo A.; Goelen, Frederik; Hertog, Thomas; Vercnocke, Bert

    2018-01-01

    Structure at the horizon scale of black holes would give rise to echoes of the gravitational wave signal associated with the postmerger ringdown phase in binary coalescences. We study the waveform of echoes in static and stationary, traversable wormholes in which perturbations are governed by a symmetric effective potential. We argue that echoes are dominated by the wormhole quasinormal frequency nearest to the fundamental black hole frequency that controls the primary signal. We put forward an accurate method to construct the echoes' waveform(s) from the primary signal and the quasinormal frequencies of the wormhole, which we characterize. We illustrate this in the static Damour-Solodukhin wormhole and in a new, rotating generalization that approximates a Kerr black hole outside the throat. Rotation gives rise to a potential with an intermediate plateau region that breaks the degeneracy of the quasinormal frequencies. Rotation also leads to late-time instabilities that, however, fade away for small angular momentum.

  7. Stellar Echo Imaging of Exoplanets, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — All stars exhibit intensity fluctuations over several time scales, from nanoseconds to days; these intensity fluctuations echo off planetary bodies in the star...

  8. Stellar Echo Imaging of Exoplanets, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — All stars exhibit intensity fluctuations over several time scales, from nanoseconds to days; these intensity fluctuations echo off planetary bodies in the star...

  9. MEASUREMENT OF TRANSVERSE ECHOES IN RHIC

    International Nuclear Information System (INIS)

    FISCHER, W.; SATOGATA, T.; TOMAS, R.

    2005-01-01

    Beam echoes are a very sensitive method to measure diffusion, and longitudinal echo measurements were performed in a number of machines. In RHIC, for the first time, a transverse beam echo was observed after applying a dipole kick followed by a quadrupole .kick. After application of the dipole kick, the dipole moment decohered completely due to lattice nonlinearities. When a quadrupole kick is applied at time τ after the dipole kick, the beam re-cohered at time 2τ thus showing an echo response. We describe the experimental setup and measurement results. In the measurements the dipole and quadrupole kick amplitudes, amplitude dependent tune shift, and the time between dipole and quadrupole kick were varied. In addition, measurements were taken with gold bunches of different intensities. These should exhibit different transverse diffusion rates due to intra-beam scattering

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  11. Hazardous Waste Dashboard Help | ECHO | US EPA

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    The dashboards found on the Enforcement and Compliance History Online (ECHO) website are specialized to track both facility and agency performance as they relate to compliance with and enforcement of environmental standards under the Resource Conservation and Recovery Act (RCRA).

  12. Transverse relaxometry with reduced echo train lengths via stimulated echo compensation.

    Science.gov (United States)

    Uddin, Md Nasir; Marc Lebel, R; Wilman, Alan H

    2013-11-01

    Transverse relaxation (T2 ) mapping has many applications, including imaging of iron accumulation in grey matter. Using the typical multiecho spin-echo sequence with long echo trains, stimulated echo compensation can enable T2 fitting under conditions of variable radio frequency homogeneity arising from slice profile and in-plane radio frequency variation. Substantial reduction in the number of refocusing pulses could enable use at high magnetic fields where specific absorption rate is a major limitation, and enable multislice use with reduced incidental magnetization transfer at all field strengths. We examine the effect of reduced echo train lengths and multislice imaging on T2 fitting using stimulated echo compensation applied to iron-rich subcortical grey matter in human brain at 4.7 T. Our findings indicate that reducing from 20 echoes to as few as four echoes can maintain consistent T2 values when using stimulated echo compensation in grey and white matter, but not for cerebrospinal fluid. All territories produce marginal results when using standard exponential fitting. Savings from reduced echoes can be used to substantially increase slice coverage. In multislice mode, the resulting incidental magnetization transfer decreased brain signal but had minimal effect on measured T2 values. Copyright © 2013 Wiley Periodicals, Inc.

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  6. Dischargers_Example.png | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  7. dashboard_1.PNG | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  8. dashboard_2.PNG | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  9. monperload_3.PNG | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  10. Drinking Water Dashboard Help | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  11. Mobile Bay.pdf | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  12. Analyze Trends: Pesticide Dashboard | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  13. Analyze Trends: State Hazardous Waste Dashboard | ECHO ...

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  14. X-ray echo spectroscopy (Conference Presentation)

    Science.gov (United States)

    Shvyd'ko, Yuri V.

    2016-09-01

    X-ray echo spectroscopy, a counterpart of neutron spin-echo, was recently introduced [1] to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a point-like x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x-rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-meV and 0.02-meV ultra-high-resolution IXS applications (resolving power > 10^8) with broadband 5-13 meV dispersing systems will be presented featuring more than 1000-fold signal enhancement. The technique is general, applicable in different photon frequency domains. [1.] Yu. Shvyd'ko, Phys. Rev. Lett. 116, accepted (2016), arXiv:1511.01526.

  15. Remedial investigation report on Bear Creek Valley Operable Unit 2 (rust spoil area, spoil area 1, and SY-200 yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 2. Appendixes

    International Nuclear Information System (INIS)

    1994-08-01

    This document contains the appendices to the Remedial Investigation Report on Bear Creek Valley Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. The appendices include Current and historical soil boring and groundwater monitoring well information, well construction logs, and field change orders; Analytical data; Human health risk assessment data; and Data quality

  16. Echoes from a Dying Star

    Science.gov (United States)

    Kohler, Susanna

    2017-06-01

    When a passing star is torn apart by a supermassive black hole, it emits a flare of X-ray, ultraviolet, and optical light. What can we learn from the infrared echo of a violent disruption like this one?Stellar DestructionOptical (black triangles) and infrared (blue circles and red squares) observations of F010042237. Day 0 marks the day the optical emission peaked. The infrared emission rises steadily through the end of the data. [Dou et al. 2017]Tidal disruption events occur when a star passes within the tidal radius of a supermassive black hole. After tidal forces pull the star apart, much of the stellar matter falls onto the black hole, radiating briefly in X-ray, ultraviolet and optical as it accretes. This signature rise and gradual fall of emission has allowed us to detect dozens of tidal disruption events thus far.One of the recently discovered candidate events is a little puzzling. Not only does the candidate in ultraluminous infrared galaxy F010042237 have an unusual host most disruptions occur in galaxies that are no longer star-forming, in contrast to this one but its optical light curve also shows an unusually long decay time.Now mid-infrared observations of this event have beenpresented by a team of scientists led by Liming Dou (Guangzhou University and Department of Education, Guangdong Province, China), revealing why this disruption is behaving unusually.Schematic of a convex dusty ring (red bows) that absorbs UV photons and re-emits in the infrared. It simultaneously scatters UV and optical photons into our line of sight. The dashed lines illustrate the delays at lags of 60 days, 1, 2, 3, 4, and 5 years. [Adapted from Dou et al. 2017]A Dusty Solution?The optical flare from F010042237s nucleus peaked in 2010, so Dou and collaborators obtained archival mid-infrared data from the WISE and NEOWISE missions from 2010 to 2016. The data show that the galaxy is quiescent in mid-infrared in 2010 but in data from three years later, the infrared emission has

  17. Acoustic Echo Cancellation Postfilter Design Issues For Speech Recognition System

    OpenAIRE

    Shrawankar, Urmila; Thakare, V M

    2013-01-01

    In this paper a generalized postfilter algorithm design issues are presented. This postfilter is used to jointly suppress late reverberation, residual echo, and background noise. When residual echo and noise are suppressed, the best result obtains by suppressing both interferences together after the Acoustic echo cancellation (AEC). The main advantage of this approach is that the residual echo and noise suppression does not suffer from the existence of a strong acoustic echo component. Furthe...

  18. Weathering processes under various moisture conditions in a lignite mine spoil from As Pontes (N.W. Spain)

    International Nuclear Information System (INIS)

    Seoane, S.; Leiros, M.C.

    1997-01-01

    Processes contributing to acid release/consumption during weathering of a lignite mine spoil (2.3% w/w S as sulfides) from As Pontes (N.W. Spain) were studied under three moisture conditions (at field capacity or under alternate wetting-drying or forced percolation), which were simulated in laboratory experiments. Oxidation of sulfides to sulfates was favoured under all three moisture conditions, releasing most acid in spoil kept at field capacity. Hydroxysulfates formed in spoil kept at field capacity or under alternate wetting-drying conditions, thereby contributing to acid release. Acid consumption by dissolution of clay minerals, especially micas, was favoured under all three moisture conditions, but was particularly intense in spoil at field capacity. Dissolution of aluminium oxides was also favoured under all the moisture conditions studied. 27 refs., 8 figs., 6 tabs

  19. The copper spoil heap Knappenberg, Austria, as a model for metal habitats – Vegetation, substrate and contamination

    Energy Technology Data Exchange (ETDEWEB)

    Adlassnig, Wolfram; Weiss, Yasmin S. [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria); Sassmann, Stefan [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria); University of Exeter, College of Life and Environmental Sciences, Biosciences, Stocker Road, Exeter EX4 4QD (United Kingdom); Steinhauser, Georg [Leibniz University Hannover, Institute of Radioecology and Radiation Protection, Herrenhäuser Straße 2, D30419 Hannover (Germany); Hofhansl, Florian [University of Vienna, Department of Microbiology and Ecosystem Science, Althanstraße 14, A-1090 Vienna (Austria); Instituto Nacional de Pesquisas da Amazônia, Coordenação de Dinâmica Ambiental, Manaus (Brazil); Baumann, Nils [Helmholtz-Zentrum Dresden-Rossendorf, Division of Biogeochemistry, Bautzner Landstraße 400, D-01328 Dresden (Germany); Lichtscheidl, Irene K. [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria); Lang, Ingeborg, E-mail: ingeborg.lang@univie.ac.at [University of Vienna, Core Facility Cell Imaging and Ultrastructure Research, Althanstraße 14, A-1090 Vienna (Austria)

    2016-09-01

    Historic mining in the Eastern Alps has left us with a legacy of numerous spoil heaps hosting specific, metal tolerant vegetation. Such habitats are characterized by elevated concentrations of toxic elements but also by high irradiation, a poorly developed substrate or extreme pH of the soil. This study investigates the distribution of vascular plants, mosses and lichens on a copper spoil heap on the ore bearing Knappenberg formed by Prebichl Layers and Werfener Schist in Lower Austria. It serves as a model for discriminating between various ecological traits and their effects on vegetation. Five distinct clusters were distinguished: (1) The bare, metal rich Central Spoil Heap was only colonised by highly resistant specialists. (2) The Northern and (3) Southern Peripheries contained less copper; the contrasting vegetation was best explained by the different microclimate. (4) A forest over acidic bedrock hosted a vegetation overlapping with the periphery of the spoil heap. (5) A forest over calcareous bedrock was similar to the spoil heap with regard to pH and humus content but hosted a vegetation differing strongly to all other habitats. Among the multiple toxic elements at the spoil heap, only Cu seems to exert a crucial influence on the vegetation pattern. Besides metal concentrations, irradiation, humidity, humus, pH and grain size distribution are important for the establishment of a metal tolerant vegetation. The difference between the species poor Northern and the diverse Southern Periphery can be explained by the microclimate rather than by the substrate. All plant species penetrating from the forest into the periphery of the spoil heap originate from the acidic but not from the calcareous bedrock. - Highlights: • Strong impact on plant diversity by isolation and extreme abiotic conditions • Both, microclimate and substrate explain species distribution. • Increased cellular metal tolerance of plants from the Central Spoil Heap • Among toxic elements

  20. Chemical properties and particle-size distribution of 39 surface-mine spoils in southern West Virginia

    Science.gov (United States)

    William T. Plass; Willis G. Vogel

    1973-01-01

    A survey of 39 surface-mine sites in southern West Virginia showed that most of the spoils from current mining operations had a pH of 5.0 or higher. Soil-size material averaged 37 percent of the weight of the spoils sampled. A major problem for the establishment of vegetation was a deficiency of nitrogen and phosphorus. This can be corrected with additions of...

  1. Heavy metals in soil on spoil heap of an abandoned lead ore ...

    African Journals Online (AJOL)

    EJIRO

    Total concentrations of 4 heavy metals (Pb, Zn, Cu, and Mn), non-metal As and three reference elements. (Ti, Fe and Al) of a soil profile on spoil heap were examined. 54 soil samples were collected in the soil profile at different depths: 15 to 45, 45 to 75, 75 to 105, 105 to 135 and 135 to 150 cm. The first 15 cm of top layer ...

  2. The development of arbuscular mycorrhiza in two simulated stages of spoil-bank succession

    Czech Academy of Sciences Publication Activity Database

    Püschel, David; Rydlová, Jana; Vosátka, Miroslav

    2007-01-01

    Roč. 35, č. 2 (2007), s. 363-369 ISSN 0929-1393 R&D Projects: GA ČR GA526/04/0996; GA ČR(CZ) GD206/03/H137 Institutional research plan: CEZ:AV0Z60050516 Keywords : mycorrhiza * plant succession * spoil bank s Subject RIV: EF - Botanics Impact factor: 1.810, year: 2007

  3. Development of Soil Characteristics and Plant Communities On Reclaimed and Unreclaimed Spoil Heaps After Coal Mining

    Science.gov (United States)

    Cudlín, Ondřej; Řehák, Zdeněk; Cudlín, Pavel

    2016-10-01

    The aim of this study was to compare soil characteristics, plant communities and the rate of selected ecosystem function performance on reclaimed and unreclaimed plots (left for spontaneous succession) of different age on spoil heaps. Twelve spoil heaps (three circle plots of radius 12.5 m) near the town Kladno in north-west direction from Prague, created after deep coal mining, were compared. Five mixed soil samples from organo-mineral horizons in each plot were analysed for total content of carbon, nitrogen and phosphorus. In addition, active soil pH (pHH2O) was determined. Plant diversity was determined by vegetation releves. The biodiversity value of the habitat according to the Habitat Valuation Method was assessed and the rate of evapotranspiration function by the Method of Valuation Functions and Services of Ecosystems in the Czech Republic were determined. The higher organo-mineral layers and higher amount of total nitrogen content were found on the older reclaimed and unreclaimed plots than in younger plots. The number of plant species and the total contents of carbon and nitrogen were significantly higher at the unreclaimed plots compared to reclaimed plots. The biodiversity values and evapotranspiration function rate were also higher on unreclaimed plots. From this perspective, it is possible to recommend using of spontaneous succession, together with routine reclamation methods to restore habitats after coal mining. Despite the relatively high age of vegetation in some of selected plots (90 years), both the reclaimed and unreclaimed plots have not reached the stage of potential vegetation near to natural climax. Slow development of vegetation was probably due to unsuitable substrate of spoil heaps and a lack of plant and tree species of natural forest habitats in this area. However, it is probable that vegetation communities on observed spoil heaps in both type of management (reclaimed and unreclaimed) will achieve the stage of natural climax and they

  4. Bottom fauna of dredging and dredge spoil disposal sites of a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Sheeba, P.; Jayalakshmy, K.V.; Devi, S.K.

    gathered at a single point in time. These studies are valuable even though they give only very little insight into the biotic constraints which are highly important in the dynamic processes which establish the real niches of animals. Niche concept.... 1967. Environmental effects of dredging and spoil deposition. Proceedings of WODCOM, World Dredging Conference (Palos Verdes Estates, California): 353-359. Heip, C. 1974. A new index measuring evenness. Journal of the Marine Biology Association (UK...

  5. Echolocation versus echo suppression in humans

    Science.gov (United States)

    Wallmeier, Ludwig; Geßele, Nikodemus; Wiegrebe, Lutz

    2013-01-01

    Several studies have shown that blind humans can gather spatial information through echolocation. However, when localizing sound sources, the precedence effect suppresses spatial information of echoes, and thereby conflicts with effective echolocation. This study investigates the interaction of echolocation and echo suppression in terms of discrimination suppression in virtual acoustic space. In the ‘Listening’ experiment, sighted subjects discriminated between positions of a single sound source, the leading or the lagging of two sources, respectively. In the ‘Echolocation’ experiment, the sources were replaced by reflectors. Here, the same subjects evaluated echoes generated in real time from self-produced vocalizations and thereby discriminated between positions of a single reflector, the leading or the lagging of two reflectors, respectively. Two key results were observed. First, sighted subjects can learn to discriminate positions of reflective surfaces echo-acoustically with accuracy comparable to sound source discrimination. Second, in the Listening experiment, the presence of the leading source affected discrimination of lagging sources much more than vice versa. In the Echolocation experiment, however, the presence of both the lead and the lag strongly affected discrimination. These data show that the classically described asymmetry in the perception of leading and lagging sounds is strongly diminished in an echolocation task. Additional control experiments showed that the effect is owing to both the direct sound of the vocalization that precedes the echoes and owing to the fact that the subjects actively vocalize in the echolocation task. PMID:23986105

  6. Remediation of Acid Generating Colliery Spoil Using Steel Slag – Case Studies

    Directory of Open Access Journals (Sweden)

    Ghataora Gurmel S.

    2015-06-01

    Full Text Available One of the legacies of the coal mining industry is the existence of numerous colliery spoil mounds. Run-off waters from some of these mounds result in oxidation of sulphur compounds causing pH to drop to perhaps as low as 2.5. At this pH, mobility for metals increases and it results in destruction of both flora and fauna. In order to reduce acidity, a number of solutions have been investigated with varying degree of success. A recent study to reduce acidity in spoil run-off water included the use of Basic Oxygen Steel slag. Its slow release of lime resulted in longer term remediation compared with other techniques. In addition to this, steel slag contains elements which are essential for plant growth and can be regarded as a weak fertiliser. This was substantiated in two field trials, which had the aim of not only remediating acidity from two different types of colliery spoils, but also to develop a composition that supports grass growth. The objectives were achieved at both sites and some of the results of over 5000 chemical tests conducted during these studies are reported in this paper.

  7. Remediation of Acid Generating Colliery Spoil Using Steel Slag - Case Studies

    Science.gov (United States)

    Ghataora, Gurmel S.; Ghazireh, Nizar; Hall, Nigel

    2015-06-01

    One of the legacies of the coal mining industry is the existence of numerous colliery spoil mounds. Run-off waters from some of these mounds result in oxidation of sulphur compounds causing pH to drop to perhaps as low as 2.5. At this pH, mobility for metals increases and it results in destruction of both flora and fauna. In order to reduce acidity, a number of solutions have been investigated with varying degree of success. A recent study to reduce acidity in spoil run-off water included the use of Basic Oxygen Steel slag. Its slow release of lime resulted in longer term remediation compared with other techniques. In addition to this, steel slag contains elements which are essential for plant growth and can be regarded as a weak fertiliser. This was substantiated in two field trials, which had the aim of not only remediating acidity from two different types of colliery spoils, but also to develop a composition that supports grass growth. The objectives were achieved at both sites and some of the results of over 5000 chemical tests conducted during these studies are reported in this paper.

  8. Impact of plantation on ecosystem development in disturbed coal mine overburden spoils

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, S.K.; Mishra, T.K.; Singh, A.K.; Jain, A. [Tropical Forest Research Inst., Jabalpur (India)

    2004-07-15

    Eleven nitrogen fixing and one non-nitrogen fixing tree species were planted in coal mine overburden spoils of Bisrampur colliery at Surguja district, Chattisgarh, India in 1993. Their growth performance at one, two, four, six and eight years was recorded. It was observed that after eight years of planting, Acacia mangium performed very well in respect to all the growth parameters followed by A. holoserecia, Dalbergia sissoo, Albiziaprocera, Pithecellobium dulce, Acacia auriculiformis and Gmelina arborea. Acacia nilotica showed very poor performance. The number of natural colonisers increased with increasing age of the planted species. Nutrient status of the spoils also increased gradually with the increase in age of the plants. Organic carbon increased greatly and, as a result, activities of bacteria, actinomycetes and fungi accelerated. This study indicated that the spoil environment, which is extremely harsh just after mining, could be improved gradually and the ecosystem restored by planting suitable species. Therefore, for early development of the ecosystem, afforestation with suitable leguminous species is recommended.

  9. Magnetization spoiling in radial FLASH contrast-enhanced MR digital subtraction angiography.

    Science.gov (United States)

    Vakil, Parmede; Ansari, Sameer A; Hurley, Michael C; Bhat, Himanshu; Batjer, H Hunt; Bendok, Bernard R; Eddleman, Christopher S; Carroll, Timothy J

    2012-07-01

    To increase the in-plane spatial resolution and image update rates of 2D magnetic resonance (MR) digital subtraction angiography (DSA) pulse sequences to 0.57 × 0.57 mm and 6 frames/sec, respectively, for intracranial vascular disease applications by developing a radial FLASH protocol and to characterize a new artifact, not previously described in the literature, which arises in the presence of such pulse sequences. The pulse sequence was optimized and artifacts were characterized using simulation and phantom studies. With Institutional Review Board (IRB) approval, the pulse sequence was used to acquire time-resolved images from healthy human volunteers and patients with x-ray DSA-confirmed intracranial vascular disease. Artifacts were shown to derive from inhomogeneous spoiling due to the nature of radial waveforms. Gradient spoiling strategies were proposed to eliminate the observed artifact by balancing gradient moments across TR intervals. The resulting radial 2D MR DSA sequence (2.6 sec temporal footprint, 6 frames/sec with sliding window factor 16, 0.57 × 0.57 mm in-plane) demonstrated small vessel detail and corroborated x-ray DSA findings in intracranial vascular imaging studies. Appropriate gradient spoiling in radial 2D MR DSA pulse sequences improves intracranial vascular depiction by eliminating circular banding artifacts. The proposed pulse sequence may provide a useful addition to clinically applied 2D MR DSA scans. Copyright © 2012 Wiley Periodicals, Inc.

  10. A controlled ac Stark echo for quantum memories.

    Science.gov (United States)

    Ham, Byoung S

    2017-08-09

    A quantum memory protocol of controlled ac Stark echoes (CASE) based on a double rephasing photon echo scheme via controlled Rabi flopping is proposed. The double rephasing scheme of photon echoes inherently satisfies the no-population inversion requirement for quantum memories, but the resultant absorptive echo remains a fundamental problem. Herein, it is reported that the first echo in the double rephasing scheme can be dynamically controlled so that it does not affect the second echo, which is accomplished by using unbalanced ac Stark shifts. Then, the second echo is coherently controlled to be emissive via controlled coherence conversion. Finally a near perfect ultralong CASE is presented using a backward echo scheme. Compared with other methods such as dc Stark echoes, the present protocol is all-optical with advantages of wavelength-selective dynamic control of quantum processing for erasing, buffering, and channel multiplexing.

  11. J-NSE: Neutron spin echo spectrometer

    Directory of Open Access Journals (Sweden)

    Olaf Holderer

    2015-08-01

    Full Text Available Neutron Spin-Echo (NSE spectroscopy is well known as the only neutron scattering technique that achieves energy resolution of several neV. By using the spin precession of polarized neutrons in magnetic field one can measure tiny velocity changes of the individual neutron during the scattering process. Contrary to other inelastic neutron scattering techniques, NSE measures the intermediate scattering function S(Q,t in reciprocal space and time directly. The Neutron Spin-Echo spectrometer J-NSE, operated by JCNS, Forschungszentrum Jülich at the Heinz Maier-Leibnitz Zentrum (MLZ in Garching, covers a time range (2 ps to 200 ns on length scales accessible by small angle scattering technique. Along with conventional NSE spectroscopy that allows bulk measurements in transmission mode, J-NSE offers a new possibility - gracing incidence spin echo spectroscopy (GINSENS, developed to be used as "push-button" option in order to resolve the depth dependent near surface dynamics.

  12. How can dolphins recognize fish according to their echoes? A statistical analysis of fish echoes.

    Directory of Open Access Journals (Sweden)

    Yossi Yovel

    Full Text Available Echo-based object classification is a fundamental task of animals that use a biosonar system. Dolphins and porpoises should be able to rely on echoes to discriminate a predator from a prey or to select a desired prey from an undesired object. Many studies have shown that dolphins and porpoises can discriminate between objects according to their echoes. All of these studies however, used unnatural objects that can be easily characterized in human terminologies (e.g., metallic spheres, disks, cylinders. In this work, we collected real fish echoes from many angles of acquisition using a sonar system that mimics the emission properties of dolphins and porpoises. We then tested two alternative statistical approaches in classifying these echoes. Our results suggest that fish species can be classified according to echoes returning from porpoise- and dolphin-like signals. These results suggest how dolphins and porpoises can classify fish based on their echoes and provide some insight as to which features might enable the classification.

  13. Short term memory in echo state networks

    OpenAIRE

    Jaeger, H.

    2001-01-01

    The report investigates the short-term memory capacity of echo state recurrent neural networks. A quantitative measure MC of short-term memory capacity is introduced. The main result is that MC 5 N for networks with linear Output units and i.i.d. input, where N is network size. Conditions under which these maximal memory capacities are realized are described. Several theoretical and practical examples demonstrate how the short-term memory capacities of echo state networks can be exploited for...

  14. Black hole ringdown echoes and howls

    Science.gov (United States)

    Nakano, Hiroyuki; Sago, Norichika; Tagoshi, Hideyuki; Tanaka, Takahiro

    2017-07-01

    Recently the possibility of detecting echoes of ringdown gravitational waves from binary black hole mergers was shown. The presence of echoes is expected if the black hole is surrounded by a mirror that reflects gravitational waves near the horizon. Here, we present slightly more sophisticated templates motivated by a waveform which is obtained by solving the linear perturbation equation around a Kerr black hole with a complete reflecting boundary condition in the stationary traveling wave approximation. We estimate that the proposed template can bring about a 10% improvement in the signal-to-noise ratio.

  15. Evolution of entanglement under echo dynamics

    International Nuclear Information System (INIS)

    Prosen, Tomaz; Znidaric, Marko; Seligman, Thomas H.

    2003-01-01

    Echo dynamics and fidelity are often used to discuss stability in quantum-information processing and quantum chaos. Yet fidelity yields no information about entanglement, the characteristic property of quantum mechanics. We study the evolution of entanglement in echo dynamics. We find qualitatively different behavior between integrable and chaotic systems on one hand and between random and coherent initial states for integrable systems on the other. For the latter the evolution of entanglement is given by a classical time scale. Analytic results are illustrated numerically in a Jaynes-Cummings model

  16. Effects of coal spoil amendment on heavy metal accumulation and physiological aspects of ryegrass (Lolium perenne L.) growing in copper mine tailings.

    Science.gov (United States)

    Chu, Zhaoxia; Wang, Xingming; Wang, Yunmin; Liu, Guijian; Dong, Zhongbing; Lu, Xianwen; Chen, Guangzhou; Zha, Fugeng

    2017-12-21

    Copper mine tailings pose many threats to the surrounding environment and human health, and thus, their remediation is fundamental. Coal spoil is the waste by-product of coal mining and characterized by low levels of metals, high content of organic matter, and many essential microelements. This study was designed to evaluate the role of coal spoil on heavy uptake and physiological responses of Lolium perenne L. grown in copper mine tailings amended with coal spoil at rates of 0, 0.5, 1, 5, 10, and 20%. The results showed that applying coal spoil to copper mine tailings decreased the diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Cu, Pb, and Zn contents in tailings and reduced those metal contents in both roots and shoots of the plant. However, application of coal spoil increased the DTPA-extractable Cr concentration in tailings and also increased Cr uptake and accumulation by Lolium perenne L. The statistical analysis of physiological parameters indicated that chlorophyll and carotenoid increased at the lower amendments of coal spoil followed by a decrease compared to their respective controls. Protein content was enhanced at all the coal spoil amendments. When treated with coal spoil, the activities of superoxide dismutases (SOD), peroxidase (POD), and catalase (CAT) responded differently. CAT activity was inhibited, but POD activity was increased with increasing amendment ratio of coal spoil. SOD activity increased up to 1% coal spoil followed by a decrease. Overall, the addition of coal spoil decreased the oxidative stress in Lolium perenne L., reflected by the reduction in malondialdehyde (MDA) contents in the plant. It is concluded that coal spoil has the potential to stabilize most metals studied in copper mine tailings and ameliorate the harmful effects in Lolium perenne L. through changing the physiological attributes of the plant grown in copper mine tailings.

  17. A virtually 1H-free birdcage coil for zero echo time MRI without background signal.

    Science.gov (United States)

    Weiger, Markus; Brunner, David O; Schmid, Thomas; Froidevaux, Romain; Rösler, Manuela B; Gross, Simon; Pruessmann, Klaas P

    2017-07-01

    MRI of tissues with rapid transverse relaxation can be performed efficiently using the zero echo time (ZTE) technique. At high bandwidths leading to large relative initial radiofrequency (RF) dead times, the method becomes increasingly sensitive to artifacts related to signal stemming from outside the field of view, particularly from the RF coils. Therefore, in this work, a birdcage coil was designed that is virtually free of 1H signal. A transmit-receive birdcage RF coil for MRI of joints at 7T was designed by rigorously avoiding materials containing 1H nuclei, by using purely mechanical connections without glue, and by spoiling of unwanted signal by application of ferromagnetic materials. The coil was tested for residual 1H signal using ZTE phantom and in vivo joint imaging. In standard ZTE imaging, no 1H signal was detected above noise level. Only at extreme averaging, residual signal was observed close to conductors associated with 1H-containing molecules at adjacent glass surfaces. Phantom images with dead times up to 3.8 Nyquist dwells were obtained with only negligible background artifacts. Furthermore, high-quality ZTE images of human joints were acquired. A virtually 1H-free birdcage coil is presented, thus enabling in vivo ZTE MRI practically free of background signal, even at high bandwidths. Magn Reson Med 78:399-407, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  18. Edaphic restoration of the spoil banks of lignite mines in Galicia. Recuperacion edafica de los escombreras de minas de lignito en Galicia. Caracterizacion de los materiales esteriles

    Energy Technology Data Exchange (ETDEWEB)

    Leiros de la Pena, M.C.; Gil Sotres, F.; Carballas Fernandez, M.; Codesido Lopez, C.; Gonzalez Sangregorio, M.V.; Seoane Lavandeira, S.; Guitian Ojea, F. (Univ. of Santiago, La Coruna (Spain). Fac. Farm., Lab. Edafol.)

    1989-01-01

    We report physical, chemical and mineralogical properties of four lignite spoils from the mines at Meirama and As Pontes (La Coruna, NW Spain). The low acidity, zero pyrite content and balanced texture of the Meirama spoils suggest that their recovery as viable soil will not be difficult, whereas recovery of the As Pontes spoils (P1 and P2) is hindered by their low pH, high total acidity and the presence of pyrites. The greatest contribution to total acidity is the residual fraction in P1 and the soluble and exchange fractions in P2. Different recovery strategies should be used for these two spoils. 2 figs., 10 tabs., 20 refs.

  19. Looking for Dust-Scattering Light Echoes

    Science.gov (United States)

    Mills, Brianna; Heinz, Sebastian; Corrales, Lia

    2018-01-01

    Galactic X-ray transient sources such as neutron stars or black holes sometimes undergo an outburst in X-rays. Ring structures have been observed around three such sources, produced by the X-ray photons being scattered by interstellar dust grains along our line of sight. These dust-scattering light echoes have proven to be a useful tool for measuring and constraining Galactic distances, mapping the dust structure of the Milky Way, and determining the dust composition in the clouds producing the echo. Detectable light echoes require a sufficient quantity of dust along our line of sight, as well as bright, short-lived Galactic X-ray flares. Using data from the Monitor of All-Sky X-ray Image (MAXI) on-board the International Space Station, we ran a peak finding algorithm in Python to look for characteristic flare events. Each flare was characterized by its fluence, the integrated flux of the flare over time. We measured the distribution of flare fluences to show how many observably bright flares were recorded by MAXI. This work provides a parent set for dust echo searches in archival X-ray data and will inform observing strategies with current and future X-ray missions such as Athena and Lynx.

  20. Data Entry Requirements | ECHO | US EPA

    Science.gov (United States)

    Data in ECHO are provided by authorized state, tribal, and local governments, and EPA Regional offices. Information is presented to help users understand where data are more complete. Many states voluntarily enter additional data that are not required; therefore, data completeness may vary widely from state to state.

  1. Pesticide Dashboard Help | ECHO | US EPA

    Science.gov (United States)

    The dashboards found on the Enforcement and Compliance History Online (ECHO) website are specialized to track both facility and agency performance as they relate to compliance with and enforcement of environmental standards under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).

  2. Echo Cancellation II: Double Talk Detection and Environmental Noise Influence

    Directory of Open Access Journals (Sweden)

    P. Sovka

    2000-04-01

    Full Text Available Two problems arising in the real-life application of echo cancellationsystems are analysed.The first, simultaneous activity of both telephoneusers (double talk deteriorates the echo suppression. The second,environmental noise is the crucial point in echo cancellation systemapplications. Experimental evaluation of the influence of bothphenomena is given together with possible solution.

  3. Robust Frequency Domain Acoustic Echo Cancellation Filter Employing Normalized Residual Echo Enhancement

    Science.gov (United States)

    Shimauchi, Suehiro; Haneda, Yoichi; Kataoka, Akitoshi

    We propose a new robust frequency domain acoustic echo cancellation filter that employs a normalized residual echo enhancement. By interpreting the conventional robust step-size control approaches as a statistical-model-based residual echo enhancement problem, the optimal step-size introduced in the most of conventional approaches is regarded as optimal only on the assumption that both the residual echo and the outlier in the error output signal are described by Gaussian distributions. However, the Gaussian-Gaussian mixture assumption does not always hold well, especially when both the residual echo and the outlier are speech signals (known as a double-talk situation). The proposed filtering scheme is based on the Gaussian-Laplacian mixture assumption for the signals normalized by the reference input signal amplitude. By comparing the performances of the proposed and conventional approaches through the simulations, we show that the Gaussian-Laplacian mixture assumption for the normalized signals can provide a better control scheme for the acoustic echo cancellation.

  4. Spatial variation in spoil and vegetative characteristics of pastures on reclaimed surface mined land

    International Nuclear Information System (INIS)

    Teutsch, C.D.; Collins, M.; Ditsch, D.C.

    1999-01-01

    Kentucky has large areas of reclaimed surface mined land that could provide grazing for livestock. Research is needed to determine optimal stocking densities and to evaluate the sustainability of such grazing systems for this region. A long-term grazing study was initiated in 1997 on 151 ha of reclaimed land near Chavies, KY to determine spatial and temporal variation with stocking densities of 0, 0.28, 0.42, or 0.83 beef cow-calf units/ha. Global Positioning System and GIS technologies were used to establish pasture boundaries, locate permanent sampling markers at a density of 1 per 0.4 ha, and interpolate maps of physical, spoil, and vegetable pasture characteristics. Herbage and spoil samples were collected around the permanent markers in May of 1997. Stepwise regression was used to determine factors affecting the vegetative characteristics of the sites. Biomass density ranged from 0 to 2500 kg/ha with a mean of 570 kg/ha. Factors affecting biomass included legume and weed proportions in the sward, grazing activity, soil potassium, elevation, and potential acidity, cumulatively accounting for 32% of the variation. Ground cover ranged from 10 to 100% with an average of 74%. Soil pH, potassium, and grass in the sward accounted for 14% of the variation in ground cover. Legumes made up 0 to 61% of the sward with a mean of 13% over the pasture area. Variables affecting the amount of legume in the sward included biomass density, slope, elevation, pH, and stocking density, together accounting for 21% of the variation. Spatial variation in the physical, spoil, and vegetative characteristics of the pastures was large. Overall, regression accounted for a limited amount of the variation in the vegetative characteristics of the site indicating that other important variables exist

  5. Anthropogenic soils on spoil rock banks in North Bohemian Coal Basin, Czech Republic

    International Nuclear Information System (INIS)

    Raclavska, H.; Raclavsky, K.; Matysek, D.; Stalmachova, B.

    1997-01-01

    The area of the North Bohemian Coal Basin is devastated by the extensive exploitation of brown coal by open pit mining. Knowledge of newly formed soils, their properties, development and contamination is important from the point of view of biological regeneration of the landscape. The mineralogy of anthropogenic soils from the mining area is presented together with the geochemistry of nutrients and trace elements. Attention is paid to the soil-forming processes in the non-reclaimed spoil rock banks with the development of spontaneous vegetation. 3 refs., 1 fig., 4 tabs

  6. Parallel imaging enhanced MR colonography using a phantom model.

    LENUS (Irish Health Repository)

    Morrin, Martina M

    2008-09-01

    To compare various Array Spatial and Sensitivity Encoding Technique (ASSET)-enhanced T2W SSFSE (single shot fast spin echo) and T1-weighted (T1W) 3D SPGR (spoiled gradient recalled echo) sequences for polyp detection and image quality at MR colonography (MRC) in a phantom model. Limitations of MRC using standard 3D SPGR T1W imaging include the long breath-hold required to cover the entire colon within one acquisition and the relatively low spatial resolution due to the long acquisition time. Parallel imaging using ASSET-enhanced T2W SSFSE and 3D T1W SPGR imaging results in much shorter imaging times, which allows for increased spatial resolution.

  7. Ecological study of revegetated coal mine spoil of an Indian dry tropical ecosystem along an age gradient.

    Science.gov (United States)

    Singh, R S; Tripathi, N; Chaulya, S K

    2012-11-01

    Mineral nitrogen (MN), belowground (root) biomass (BGB), soil nitrogen (N) mineralization (NM), microbial biomass N (MBN) and mine dump stability of a revegetated mine spoil were studied after 2, 6, 10 and 12 years of re-vegetation on coal mine spoil site. MN in revegetated mine spoil ranged from 7.4 to 11.6 kg ha(-1), NM from 38.4 to 252 kg ha(-1) year(-1), MBN from 86 to 426 kg ha(-1), and BGB from 380 to 3,750 kg ha(-1). Mining caused decline of physico-chemical characteristics of soil like MN by 46 %, N-mineralization by 92 %, MBN values by 91 %, respectively compared to forest ecosystems and reduction of total plant biomass (above ground and below ground). Revegetation of mine spoil caused increase in MN values by 12, 36 and 76 %, BGB values by 380, 1770 and 3750 times, NM values by 0.6, 3.58 and 9.5 times and MBN values by 0.43, 2.77, and 6.07 times in 2, 6 and 12 years, respectively. BGB was highly correlated with MN and MBN. Clay content was positively correlated to MN, NM, and the age of revegetation (P < 0.01). Numerical modelling indicated that revegetation increased the dump slope stability with a factor of safety from 1.2 to 1.4, 1.7, 1.9 and 2.1 after 2, 6, 10 and 12 years, respectively. Thus, long-term revegetation was found to enhance the dump stability and the soil fertility status in mine spoil, where plant biomass and microbial biomass provide major contributions in ecological redevelopment of the mine spoil.

  8. Ultrasonic unipolar pulse/echo instrument

    Science.gov (United States)

    Hughes, M.J.; Hsu, D.K.; Thompson, D.O.; Wormley, S.J.

    1993-04-06

    An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

  9. Workshop on neutron spin-echo

    Energy Technology Data Exchange (ETDEWEB)

    Aynajian, P.; Habicht, K.; Keller, Th.; Keimer, B.; Mezei, F.; Monkenbusch, M.; Allgaier, J.; Richter, D.; Fetters, L.J.; Muller, K.; Kreiling, S.; Dehnicke, K.; Greiner, A.; Ehlers, G.; Arbe, A.; Colmenero, J.; Richter, D.; Farago, B.; Monkenbusch, M.; Ohl, M.; Butzek, M.; Kozielewski, T.; Monkenbusch, M.; Richter, D.; Pappas, C.; Hillier, A.; Manuel, P.; Cywinski, R.; Bentley, P.; Alba, M.; Mezei, F.; Campbell, I.A.; Zimmermann, U.; Ellis, J.; Jobic, H.; Pickup, R.M.; Pappas, C.; Farago, B.; Cywinski, R.; Haussler, W.; Holderer, O.; Frielinghaus, H.; Byelov, D.; Monkenbusch, M.; Allgaier, J.; Richter, D.; Egger, H.; Hellweg, Th.; Malikova, N.; Cadene, A.; Marry, V.; Dubois, E.; Turq, P.; Gardner, J.S.; Ehlers, G.; Bramwell, St.S.; Grigoriev, S.; Kraan, W.; Rekveldt, T.; Bouwman, W.; Van Dijk, N.; Falus, P.; Vorobiev, A.; Major, J.; Felcher, G.P.; Te-velthuis, S.; Dosch, H.; Vorobiev, A.; Dridi, M.H.; Major, J.; Dosch, H.; Falus, P.; Felcher, G.P.; Te Velthuis, S.G.E.; Bleuel, M.; Broell, M.; Lang, E.; Littrell, K.; Gahler, R.; Lal, J.; Lauter, H.; Toperverg, B.; Lauter, V.; Jernenkov, M.; Stueber, S.; Enderle, M.; Janoschek, M.; Keller, Th.; Klimko, S.; Boeni, P.; Nagao, M.; Yamada, N.; Kawabata, Y.; Seto, H.; Takeda, T.; Yoshizawa, H.; Yoshida, K.; Yamaguchi, T.; Bellissent-Funel, M.C.; Longeville, St

    2005-07-01

    This document gathers the abstracts of most papers presented at the workshop. Neutron spin-echo (NSE) spectroscopy is a well established technique with a growing expert user community, the aim of the meeting was to discuss the latest achievements in neutron spin-echo science and instrumentation. One of the applications presented is the investigation on the microscopic scale of the dynamics of water in montmorillonite clays with Na{sup +} and Cs{sup +} ions in monolayer and bilayer states. The NSE technique has been used in the normal and resonance modes. NSE results show consistently slower dynamics (higher relaxation times) than both time-of-flight technique (TOF) and classical molecular dynamics simulations (MD). In the present TOF and NSE experiments, anisotropy of the water motion in the interlayer is almost impossible to detect, due to the use of powder samples and insufficient resolution. (A.C.)

  10. Acidification - neutralization processes in a lignite mine spoil amended with fly ash or limestone

    Energy Technology Data Exchange (ETDEWEB)

    Seoane, S.; Leiros, M.C. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain). Dept. de Edafologia y Quimica Agricola

    2001-08-01

    A laboratory experiment was conducted to investigate the long-term effects of amending sulfide-rich lignite mine spoil with fly ash (originating from a coal-fired power station and largely comprised of aluminosilicates) and/or agricultural limestone. The experiment was carried out with soil moisture maintained at field capacity or alternate cycles of wetting and drying. Results obtained suggest that the principal acidification processes were oxidation of sulfide and formation of hydroxysulfate (FeOHSO{sub 4}), whereas the main neutralization processes were weathering of aluminosilicates in fly ash-treated samples. The highest dose of limestone rapidly raised the pH of the spoil, but this increase was not maintained throughout the one-year experiment. In contrast, fly ash-treated samples showed a more sustained increase in pH, attributable to the gradual weathering of aluminosilicates. The best results (i.e., good short- and long-term neutralization) were obtained in samples treated with both fly ash and limestone. The low liming capacity of the fly ash (47.85 cmol kg{sup -1}) means that it must be used in large quantities, an advantage in achieving the further aim of disposing of the fly ash. 33 refs., 5 figs., 4 tabs.

  11. Single-shot echo-planar imaging of multiple sclerosis: effects of varying echo time

    International Nuclear Information System (INIS)

    Wolansky, L.J.; Chong, S.; Liu, W.C.; Kang, E.; Simpson, S.W.; Karimi, S.; Akbari, H.

    1999-01-01

    Our aim was to determine the relative merits of short and long echo times (TE) with single-shot echo-planar imaging for imaging cerebral lesions such as multiple sclerosis. We examined seven patients with clinically definite multiple sclerosis were imaged at 1.5 T. Patients were scanned with spin-echo, single-shot echo-planar imaging, using TEs of 45, 75, 105, and 135 ms. Region of interest (ROI) measurements were performed on 36 lesions at or above the level of the corona radiata. The mean image contrast (IC) was highest (231.1) for a TE of 45 ms, followed by 75 ms (218.9), 105 ms (217.9), and 135 ms (191.6). When mean contrast-to-noise ratios (C/N) were compared, the value was again highest (29.7) for TE 45 ms, followed by 75 ms (28.9), 105 ms (28.5), and 135 ms (26.3). In a lesion-by-lesion comparison, TE 45 ms had the highest IC and C/N in the largest number of cases (50 % and 47.2 %, respectively). IC and C/N for TE 45 ms were superior to those of 75 ms in 64 % and 58 %, respectively. These results support the use of relatively short TEs for single-shot echo-planar imaging in the setting of cerebral lesions such as multiple sclerosis. (orig.) (orig.)

  12. Conventional and fast spin-echo MR imaging: minimizing echo time.

    Science.gov (United States)

    Vinitski, S; Mitchell, D G; Einstein, S G; Rao, V M; Flanders, A E; Schweitzer, M E; Listerud, J; Schnall, M D

    1993-01-01

    Magnetic resonance imaging is frequently complicated by the presence of motion and susceptibility gradients. Also, some biologic tissues have short T2s. These problems are particularly troublesome in fast spin-echo (FSE) imaging, in which T2 decay and motion between echoes result in image blurring and ghost artifacts. The authors reduced TE in conventional spin-echo (SE) imaging to 5 msec and echo spacing (E-space) in FSE imaging to 6 msec. All magnetic gradients (except readout) were kept at a maximum, with data sampling as fast as 125 kHz and only ramp waveforms used. Truncated sinc radio-frequency pulses and asymmetric echo sampling were also used in SE imaging. Short TE (5.8 msec) SE images of the upper abdomen were compared with conventional SE images (TE = 11 msec). Also, FSE images with short E-space were compared with conventional FSE images in multiple body sites. Short TE significantly improved the liver-spleen contrast-to-total noise ratio (C/N) (7.9 vs 4.1, n = 9, P crisper and measured spleen-liver C/N increased significantly (6.9 vs 4.0, n = 12, P < .01). The delineation of tissues with short T2 (eg, cartilage) and motion artifact suppression were also improved. Short TE methods can improve image quality in both SE and FSE imaging and merit further clinical evaluation.

  13. Temperature sheets and aspect sensitive radar echoes

    Directory of Open Access Journals (Sweden)

    H. Luce

    Full Text Available here have been years of discussion and controversy about the existence of very thin and stable temperature sheets and their relationship to the VHF radar aspect sensitivity. It is only recently that very high-resolution in situ temperature observations have brought credence to the reality and ubiquity of these structures in the free atmosphere and to their contribution to radar echo enhancements along the vertical. Indeed, measurements with very high-resolution sensors are still extremely rare and rather difficult to obtain outside of the planetary boundary layer. They have only been carried out up to the lower stratosphere by Service d’A´ eronomie (CNRS, France for about 10 years. The controversy also persisted due to the volume resolution of the (Mesosphere-Stratosphere-Troposphere VHF radars which is coarse with respect to sheet thickness, although widely sufficient for meteorological or mesoscale investigations. The contribution within the range gate of many of these structures, which are advected by the wind, and decay and grow at different instants and could be distorted either by internal gravity waves or turbulence fields, could lead to radar echoes with statistical properties similar to those produced by anisotropic turbulence. Some questions thus remain regarding the manner in which temperature sheets contribute to VHF radar echoes. In particular, the zenithal and azimuthal angular dependence of the echo power may not only be produced by diffuse reflection on stable distorted or corrugated sheets, but also by extra contributions from anisotropic turbulence occurring in the stratified atmosphere. Thus, for several years, efforts have been put forth to improve the radar height resolution in order to better describe thin structures. Frequency interferometric techniques are widely used and have been recently further developed with the implementation of high-resolution data processings. We begin by reviewing briefly some characteristics

  14. Temperature sheets and aspect sensitive radar echoes

    Directory of Open Access Journals (Sweden)

    H. Luce

    2001-08-01

    Full Text Available here have been years of discussion and controversy about the existence of very thin and stable temperature sheets and their relationship to the VHF radar aspect sensitivity. It is only recently that very high-resolution in situ temperature observations have brought credence to the reality and ubiquity of these structures in the free atmosphere and to their contribution to radar echo enhancements along the vertical. Indeed, measurements with very high-resolution sensors are still extremely rare and rather difficult to obtain outside of the planetary boundary layer. They have only been carried out up to the lower stratosphere by Service d’A´ eronomie (CNRS, France for about 10 years. The controversy also persisted due to the volume resolution of the (Mesosphere-Stratosphere-Troposphere VHF radars which is coarse with respect to sheet thickness, although widely sufficient for meteorological or mesoscale investigations. The contribution within the range gate of many of these structures, which are advected by the wind, and decay and grow at different instants and could be distorted either by internal gravity waves or turbulence fields, could lead to radar echoes with statistical properties similar to those produced by anisotropic turbulence. Some questions thus remain regarding the manner in which temperature sheets contribute to VHF radar echoes. In particular, the zenithal and azimuthal angular dependence of the echo power may not only be produced by diffuse reflection on stable distorted or corrugated sheets, but also by extra contributions from anisotropic turbulence occurring in the stratified atmosphere. Thus, for several years, efforts have been put forth to improve the radar height resolution in order to better describe thin structures. Frequency interferometric techniques are widely used and have been recently further developed with the implementation of high-resolution data processings. We begin by reviewing briefly some characteristics

  15. The EChO science case

    Science.gov (United States)

    Tinetti, Giovanna; Drossart, Pierre; Eccleston, Paul; Hartogh, Paul; Isaak, Kate; Linder, Martin; Lovis, Christophe; Micela, Giusi; Ollivier, Marc; Puig, Ludovic; Ribas, Ignasi; Snellen, Ignas; Swinyard, Bruce; Allard, France; Barstow, Joanna; Cho, James; Coustenis, Athena; Cockell, Charles; Correia, Alexandre; Decin, Leen; de Kok, Remco; Deroo, Pieter; Encrenaz, Therese; Forget, Francois; Glasse, Alistair; Griffith, Caitlin; Guillot, Tristan; Koskinen, Tommi; Lammer, Helmut; Leconte, Jeremy; Maxted, Pierre; Mueller-Wodarg, Ingo; Nelson, Richard; North, Chris; Pallé, Enric; Pagano, Isabella; Piccioni, Guseppe; Pinfield, David; Selsis, Franck; Sozzetti, Alessandro; Stixrude, Lars; Tennyson, Jonathan; Turrini, Diego; Zapatero-Osorio, Mariarosa; Beaulieu, Jean-Philippe; Grodent, Denis; Guedel, Manuel; Luz, David; Nørgaard-Nielsen, Hans Ulrik; Ray, Tom; Rickman, Hans; Selig, Avri; Swain, Mark; Banaszkiewicz, Marek; Barlow, Mike; Bowles, Neil; Branduardi-Raymont, Graziella; du Foresto, Vincent Coudé; Gerard, Jean-Claude; Gizon, Laurent; Hornstrup, Allan; Jarchow, Christopher; Kerschbaum, Franz; Kovacs, Géza; Lagage, Pierre-Olivier; Lim, Tanya; Lopez-Morales, Mercedes; Malaguti, Giuseppe; Pace, Emanuele; Pascale, Enzo; Vandenbussche, Bart; Wright, Gillian; Ramos Zapata, Gonzalo; Adriani, Alberto; Azzollini, Ruymán; Balado, Ana; Bryson, Ian; Burston, Raymond; Colomé, Josep; Crook, Martin; Di Giorgio, Anna; Griffin, Matt; Hoogeveen, Ruud; Ottensamer, Roland; Irshad, Ranah; Middleton, Kevin; Morgante, Gianluca; Pinsard, Frederic; Rataj, Mirek; Reess, Jean-Michel; Savini, Giorgio; Schrader, Jan-Rutger; Stamper, Richard; Winter, Berend; Abe, L.; Abreu, M.; Achilleos, N.; Ade, P.; Adybekian, V.; Affer, L.; Agnor, C.; Agundez, M.; Alard, C.; Alcala, J.; Allende Prieto, C.; Alonso Floriano, F. J.; Altieri, F.; Alvarez Iglesias, C. A.; Amado, P.; Andersen, A.; Aylward, A.; Baffa, C.; Bakos, G.; Ballerini, P.; Banaszkiewicz, M.; Barber, R. J.; Barrado, D.; Barton, E. J.; Batista, V.; Bellucci, G.; Belmonte Avilés, J. A.; Berry, D.; Bézard, B.; Biondi, D.; Błęcka, M.; Boisse, I.; Bonfond, B.; Bordé, P.; Börner, P.; Bouy, H.; Brown, L.; Buchhave, L.; Budaj, J.; Bulgarelli, A.; Burleigh, M.; Cabral, A.; Capria, M. T.; Cassan, A.; Cavarroc, C.; Cecchi-Pestellini, C.; Cerulli, R.; Chadney, J.; Chamberlain, S.; Charnoz, S.; Christian Jessen, N.; Ciaravella, A.; Claret, A.; Claudi, R.; Coates, A.; Cole, R.; Collura, A.; Cordier, D.; Covino, E.; Danielski, C.; Damasso, M.; Deeg, H. J.; Delgado-Mena, E.; Del Vecchio, C.; Demangeon, O.; De Sio, A.; De Wit, J.; Dobrijévic, M.; Doel, P.; Dominic, C.; Dorfi, E.; Eales, S.; Eiroa, C.; Espinoza Contreras, M.; Esposito, M.; Eymet, V.; Fabrizio, N.; Fernández, M.; Femenía Castella, B.; Figueira, P.; Filacchione, G.; Fletcher, L.; Focardi, M.; Fossey, S.; Fouqué, P.; Frith, J.; Galand, M.; Gambicorti, L.; Gaulme, P.; García López, R. J.; Garcia-Piquer, A.; Gear, W.; Gerard, J.-C.; Gesa, L.; Giani, E.; Gianotti, F.; Gillon, M.; Giro, E.; Giuranna, M.; Gomez, H.; Gomez-Leal, I.; Gonzalez Hernandez, J.; González Merino, B.; Graczyk, R.; Grassi, D.; Guardia, J.; Guio, P.; Gustin, J.; Hargrave, P.; Haigh, J.; Hébrard, E.; Heiter, U.; Heredero, R. L.; Herrero, E.; Hersant, F.; Heyrovsky, D.; Hollis, M.; Hubert, B.; Hueso, R.; Israelian, G.; Iro, N.; Irwin, P.; Jacquemoud, S.; Jones, G.; Jones, H.; Justtanont, K.; Kehoe, T.; Kerschbaum, F.; Kerins, E.; Kervella, P.; Kipping, D.; Koskinen, T.; Krupp, N.; Lahav, O.; Laken, B.; Lanza, N.; Lellouch, E.; Leto, G.; Licandro Goldaracena, J.; Lithgow-Bertelloni, C.; Liu, S. J.; Lo Cicero, U.; Lodieu, N.; Lognonné, P.; Lopez-Puertas, M.; Lopez-Valverde, M. A.; Lundgaard Rasmussen, I.; Luntzer, A.; Machado, P.; MacTavish, C.; Maggio, A.; Maillard, J.-P.; Magnes, W.; Maldonado, J.; Mall, U.; Marquette, J.-B.; Mauskopf, P.; Massi, F.; Maurin, A.-S.; Medvedev, A.; Michaut, C.; Miles-Paez, P.; Montalto, M.; Montañés Rodríguez, P.; Monteiro, M.; Montes, D.; Morais, H.; Morales, J. C.; Morales-Calderón, M.; Morello, G.; Moro Martín, A.; Moses, J.; Moya Bedon, A.; Murgas Alcaino, F.; Oliva, E.; Orton, G.; Palla, F.; Pancrazzi, M.; Pantin, E.; Parmentier, V.; Parviainen, H.; Peña Ramírez, K. Y.; Peralta, J.; Perez-Hoyos, S.; Petrov, R.; Pezzuto, S.; Pietrzak, R.; Pilat-Lohinger, E.; Piskunov, N.; Prinja, R.; Prisinzano, L.; Polichtchouk, I.; Poretti, E.; Radioti, A.; Ramos, A. A.; Rank-Lüftinger, T.; Read, P.; Readorn, K.; Rebolo López, R.; Rebordão, J.; Rengel, M.; Rezac, L.; Rocchetto, M.; Rodler, F.; Sánchez Béjar, V. J.; Sanchez Lavega, A.; Sanromá, E.; Santos, N.; Sanz Forcada, J.; Scandariato, G.; Schmider, F.-X.; Scholz, A.; Scuderi, S.; Sethenadh, J.; Shore, S.; Showman, A.; Sicardy, B.; Sitek, P.; Smith, A.; Soret, L.; Sousa, S.; Stiepen, A.; Stolarski, M.; Strazzulla, G.; Tabernero, H. M.; Tanga, P.; Tecsa, M.; Temple, J.; Terenzi, L.; Tessenyi, M.; Testi, L.; Thompson, S.; Thrastarson, H.; Tingley, B. W.; Trifoglio, M.; Martín Torres, J.; Tozzi, A.; Turrini, D.; Varley, R.; Vakili, F.; de Val-Borro, M.; Valdivieso, M. L.; Venot, O.; Villaver, E.; Vinatier, S.; Viti, S.; Waldmann, I.; Waltham, D.; Ward-Thompson, D.; Waters, R.; Watkins, C.; Watson, D.; Wawer, P.; Wawrzaszk, A.; White, G.; Widemann, T.; Winek, W.; Wiśniowski, T.; Yelle, R.; Yung, Y.; Yurchenko, S. N.

    2015-12-01

    The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune—all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10-4 relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength

  16. Colonization of colliery spoil heaps by millipedes (Diplopoda) and terrestrial isopods (Oniscidea) in the Sokolov region, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Tajovský, Karel

    2001-01-01

    Roč. 9, č. 4 (2001), s. 365-369 ISSN 1061-2971 Institutional research plan: CEZ:AV0Z6066911 Keywords : colliery spoil heaps * succession * rekultivation Subject RIV: EH - Ecology, Behaviour Impact factor: 1.011, year: 2001

  17. Efficacy of Designer Biochars with or without Lime Application for Remediating Heavy Metals in Mine Spoil Soils

    Science.gov (United States)

    Sigua, Gilbert C.; Novak, Jeffrey; Johnson, Mark; Ippolito, James; Spokas, Kurt; Ducey, Thomas; Trippe, Kristin

    2017-04-01

    A multitude of research investigations have confirmed that biochars can increase soil carbon sequestration, improve critical plant nutrient concentrations, and improve the fertility, chemical, and physical properties of degraded agricultural soils. Recently, biochars ability to sequester metals has caught the attention of the mine reclamation sector. It is proposed that biochar is a suitable amendment to remediate heavy metals in mine spoils, as well as improve chemical conditions for enhanced plant growth. Better plant growth will improve phytostabilization, increase containment of metal-laden sediment, while also reducing potential metal uptake by plants. As such, utilization of a biochar with appropriate chemical and physical characteristics is crucial for effective binding of heavy metals while also improving plant growth conditions in mine spoils. Using two different mine spoils, we conducted laboratory and greenhouse experiments to determine the ability of designer biochar with or without lime application to favorably improve soil pH, reduce heavy metal bioavailability, and improve grass (e.g., wild blue rye) plant nutrient uptake. Preliminary results showed that our designer biochars did increase pH of acid mine spoils significantly (pheavy metals (e.g. aluminum, chromium, zinc, nickel, zinc, manganese, copper and cadmium) in the soils.

  18. Echo Shaping Using Sums of Damped Complex Sinusoids

    DEFF Research Database (Denmark)

    Putnam, Lance Jonathan

    2015-01-01

    Feedback delay lines are the basis of myriad audio effects and reverberation schemes. The feedback delay line, by itself, is limited to producing an infinite sequence of exponentially decaying echoes. We introduce a new type of linear time-invariant echo effect whose impulse response...... be used to produce auto-panning echo effects with many kinds of spatial trajectories. The effect is computationally efficient and straightforward to implement, as it only requires a parallel combination of feedback delay lines....

  19. Dump stability and soil fertility of a coal mine spoil in Indian dry tropical environment: a long-term study.

    Science.gov (United States)

    Tripathi, Nimisha; Singh, Raj Shekhar; Chaulya, Swadesh K

    2012-10-01

    Plant available nitrogen, belowground (root) biomass, soil nitrogen (N) mineralization and microbial biomass N (MBN) were studied for 12 years at the interval of 2 years (0, 2, 4, 6, 8, 10 and 12 years) and mine dump stability at the intervals of 6 years (0, 6 and 12 years) after re-vegetation on coal mine spoil site. Plant available nitrogen in revegetated mine spoil ranged from 4.51 to 6.59 μg g(-1), net N-mineralization from 1.87 to 13.85 μg g(-1) month(-1), MBN from 10 to 22.63 μg g(-1), and root biomass from 28 to 566 g(-2). Mining activity has caused a change in soil characteristics including plant available nutrients like nitrate-N, ammonium-N and phosphate-P by 70, 67, and 76 %, respectively, N-mineralization by 93 %, root biomass values by 97 % and MBN values by 91 % compared to forest ecosystems. Revegetation of mine spoil produced increase in root biomass values by 1.3, 7.6 and 17.2 times, mineral N values by 1.22, 1.43 and 1.79 times, N-mineralization values by 1.8, 5.2 and 12.6 times and MBN values by 1.6, 2.0, and 3.4 times in 2, 6 and 12 years, respectively. Below ground biomass was highly co-related with microbial biomass and plant available nutrients. N-mineralization, plant available nutrients and the clay content were positively correlated with age of revegetation (P soil fertility status in mine spoil, where plant biomass and microbial biomass provide major contributions in ecological redevelopment of the mine spoil.

  20. Contribution of arbuscular mycorrhizal fungi to the development of maize (Zea mays L.) grown in three types of coal mine spoils.

    Science.gov (United States)

    Guo, Wei; Zhao, Renxin; Fu, Ruiying; Bi, Na; Wang, Lixin; Zhao, Wenjing; Guo, Jiangyuan; Zhang, Jun

    2014-03-01

    Coal mine spoils are usually unfavorable for plant growth and have different properties according to dumping years, weathering degree, and the occurrence of spontaneous combustion. The establishment of plant cover in mine spoils can be facilitated by arbuscular mycorrhizal fungi (AMF). A greenhouse pot experiment was conducted to evaluate the importance of AMF in plant adaptation to different mine spoils and the potential role of AMF for revegetation practices. We investigated the effects of Glomus aggregatum, Rhizophagus intraradices (syn. Glomus intraradices), and Funneliformis mosseae (syn. Glomus mosseae) on the growth, nutritional status, and metal uptake of maize (Zea mays L.) grown in recent discharged (S1), weathered (S2), and spontaneous combusted (S3) coal mine spoils. Symbiotic associations were successfully established between AMF and maize in three substrates. Mycorrhizal colonization effectively promoted plant growth by significantly increasing the uptake of nitrogen (N), phosphorus (P), and potassium (K), adjusting C:N:P stoichiometry and alleviating toxic effects of heavy metals. G. aggregatum, R. intraradices, and F. mosseae exhibited different mycorrhizal effects in response to mine spoil types. F. mosseae was the most effective in the development of maize in S1 and may be the most appropriate for revegetation of this substrate, while R. intraradices played the most beneficial role in S2 and S3. Our results suggest that inoculation with AMF can enhance plant adaptation to different types of coal mine spoils and play a positive role in the revegetation of coal mine spoil banks.

  1. The EChO science case

    DEFF Research Database (Denmark)

    Tinetti, Giovanna; Drossart, Pierre; Eccleston, Paul

    2015-01-01

    measurements of their radii and masses would allow degeneracies associated with planetary interior modelling to be broken, giving unique insight into the interior structure and elemental abundances of these alien worlds. EChO would allow scientists to study exoplanets both as a population and as individuals......), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO’s launch and enable the atmospheric characterisation of hundreds of planets....

  2. Behavior of Psychrotrophic Lactic Acid Bacteria Isolated from Spoiling Cooked Meat Products

    Science.gov (United States)

    Hamasaki, Yoshikatsu; Ayaki, Mitsuko; Fuchu, Hidetaka; Sugiyama, Masaaki; Morita, Hidetoshi

    2003-01-01

    Three kinds of lactic acid bacteria were isolated from spoiling cooked meat products stored below 10°C. They were identified as Leuconostoc mesenteroides subsp. mesenteroides, Lactococcus lactis subsp. lactis, and Leuconostoc citreum. All three strains grew well in MRS broth at 10°C. In particular, L. mesenteroides subsp. mesenteroides and L. citreum grew even at 4°C, and their doubling times were 23.6 and 51.5 h, respectively. On the other hand, although the bacteria were initially below the detection limit (<10 CFU/g) in model cooked meat products, the bacterial counts increased to 108 CFU/g at 10°C after 7 to 12 days. PMID:12788779

  3. Room Geometry Estimation from Acoustic Echoes using Graph-Based Echo Labeling

    NARCIS (Netherlands)

    Jager, Ingmar; Heusdens, R.; Gaubitch, N.D.; Dong, Min; Zheng, Thomas Fang

    2016-01-01

    A computer being able to estimate the geometry of a room could benefit applications such as auralization, robot navigation, virtual reality and teleconferencing. When estimating the geometry of a room using multiple microphones, the main challenge is to identify which reflections, or echoes,

  4. Selenium transformation in coal mine spoils: Its environmental impact assessment. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Harness, J.; Atalay, A.; Koll, K.J.; Zhang, H.; Maggon, D.

    1991-12-31

    The objective of this program was to conduct an environmental impact assessment study for selenium from coal mine spoils. The use of in-situ lysimetry to predict selenium speciation, transformation, and mobility under natural conditions was evaluated. The scope of the study was to construct and test field-scale lysimeter and laboratory mini-column to assess mobility and speciation of selenium in coal mine overburden and soil systems; to conduct soil and groundwater sampling throughout the state of Oklahoma for an overall environmental impact assessment of selenium; and to conduct an in-depth literature review on the solubility, speciation, mobility, and toxicity of selenium from various sources. Groundwater and surface soil samples were also collected from each county in Oklahoma. Data collected from the lysimeter study indicated that selenium in the overburden of the abandoned mine site was mainly found in the selenite form. The amount of selenite found was too low and immobile to be of concern to the environment. The spoil had equilibrated long enough (over 50 years) that most of the soluble forms of selenium have already been lost. Examination of the overburden indicated the presence of pyrite crystals that precipitated over time. The laboratory mini-column study indicated that selenite is quite immobile and remained on the overburden material even after leaching with dilute acid. Data from groundwater samples indicated that based on the current permissible level for selenium in groundwater (0.01 mg Se/L), Oklahoma groundwater is widely contaminated with the element. However, according to the new regulation (0.05 mg Se/L), which is to be promulgated in 1992, only 9 of the 77 counties in the state exceed the limit.

  5. Three-dimensional MR imaging in the assessment of physeal growth arrest

    International Nuclear Information System (INIS)

    Sailhan, Frederic; Chotel, Franck; Gollogly, Sohrab; Adam, Philippe; Berard, Jerome; Guibal, Anne-Laure; Guibaud, Laurent

    2004-01-01

    The purpose of this study is to describe an imaging method for identifying and characterising physeal growth arrest following physeal plate aggression. The authors describe the use of three-dimensional MRI performed with fat-suppressed three-dimensional spoiled gradient-recalled echo sequences followed by manual image reconstruction to create a 3D model of the physeal plate. This retrospective series reports the analysis of 33 bony physeal bridges in 28 children (mean age 10.5 years) with the use of fat-suppressed three-dimensional spoiled gradient-recalled echo imaging and 3D reconstructions from the source images. 3D reconstructions were obtained after the outlining was done manually on each source image. Files of all patients were reviewed for clinical data at the time of MRI, type of injury, age at MRI and bone bridge characteristics on reconstructions. Twenty-one (63%) of the 33 bridges were post-traumatic and were mostly situated in the lower extremities (19/21). The distal tibia was involved in 66% (14/21) of the cases. Bridges due to causes other than trauma were located in the lower extremities in 10/12 cases, and the distal femur represented 60% of these cases. Of the 28 patients, five presented with two bridges involving two different growth plates making a total of 33 physeal bone bars. The location and shape of each bridge was accurately identified in each patient, and in post-traumatic cases, 89% of bone bars were of Ogden type III (central) or I (peripheral). Reconstructions were obtained in 15 min and are easy to interpret. Volumes of the physeal bone bridge(s) and of the remaining normal physis were calculated. The bone bridging represented less than 1% to 47% of the total physeal plate volume. The precise shape and location of the bridge can be visualised on the 3D reconstructions. This information is useful in the surgical management of these deformities; as for the eight patients who underwent bone bar resection, an excellent correspondence was

  6. On Stellar Flash Echoes from Circular Rings

    Science.gov (United States)

    Nemiroff, Robert; Mukherjee, Oindabi

    2018-01-01

    A flash -- or any episode of variability -- that occurs in the vicinity of a circular ring might be seen several times later, simultaneously, as echoes on the ring. Effective images of the flash are created and annihilated in pairs, with as many as four flash images visible concurrently. Videos detailing sequences of image pair creation, tandem motion, and subsequent image annihilation are shown, given simple opacity and scattering assumptions. It is proven that, surprisingly, images from a second pair creation event always annihilate with images from the first. Caustic surfaces between flash locations yielding two and four images are computed. Although such ring echos surely occur, their practical detection might be difficult as it could require dedicated observing programs involving sensitive photometry of extended objects. Potential flash sources include planetary and interstellar gas and dust rings near and around variable stars, flare stars, novae, supernovae, and GRBs. Potentially recoverable information includes size, distance, temporal history, and angular isotropy of both the ring and flash.

  7. Triple echo steady-state (TESS) relaxometry.

    Science.gov (United States)

    Heule, Rahel; Ganter, Carl; Bieri, Oliver

    2014-01-01

    Rapid imaging techniques have attracted increased interest for relaxometry, but none are perfect: they are prone to static (B0 ) and transmit (B1 ) field heterogeneities, and commonly biased by T2 /T1 . The purpose of this study is the development of a rapid T1 and T2 relaxometry method that is completely (T2 ) or partly (T1 ) bias-free. A new method is introduced to simultaneously quantify T1 and T2 within one single scan based on a triple echo steady-state (TESS) approach in combination with an iterative golden section search. TESS relaxometry is optimized and evaluated from simulations, in vitro studies, and in vivo experiments. It is found that relaxometry with TESS is not biased by T2 /T1 , insensitive to B0 heterogeneities, and, surprisingly, that TESS-T2 is not affected by B1 field errors. Consequently, excellent correspondence between TESS and reference spin echo data is observed for T2 in vitro at 1.5 T and in vivo at 3 T. TESS offers rapid T1 and T2 quantification within one single scan, and in particular B1 -insensitive T2 estimation. As a result, the new proposed method is of high interest for fast and reliable high-resolution T2 mapping, especially of the musculoskeletal system at high to ultra-high fields. Copyright © 2013 Wiley Periodicals, Inc.

  8. Magnetic resonance fingerprinting using echo-planar imaging: Joint quantification of T1and T2∗ relaxation times.

    Science.gov (United States)

    Rieger, Benedikt; Zimmer, Fabian; Zapp, Jascha; Weingärtner, Sebastian; Schad, Lothar R

    2017-11-01

    To develop an implementation of the magnetic resonance fingerprinting (MRF) paradigm for quantitative imaging using echo-planar imaging (EPI) for simultaneous assessment of T 1 and T2∗. The proposed MRF method (MRF-EPI) is based on the acquisition of 160 gradient-spoiled EPI images with rapid, parallel-imaging accelerated, Cartesian readout and a measurement time of 10 s per slice. Contrast variation is induced using an initial inversion pulse, and varying the flip angles, echo times, and repetition times throughout the sequence. Joint quantification of T 1 and T2∗ is performed using dictionary matching with integrated B1+ correction. The quantification accuracy of the method was validated in phantom scans and in vivo in 6 healthy subjects. Joint T 1 and T2∗ parameter maps acquired with MRF-EPI in phantoms are in good agreement with reference measurements, showing deviations under 5% and 4% for T 1 and T2∗, respectively. In vivo baseline images were visually free of artifacts. In vivo relaxation times are in good agreement with gold-standard techniques (deviation T 1 : 4 ± 2%, T2∗: 4 ± 5%). The visual quality was comparable to the in vivo gold standard, despite substantially shortened scan times. The proposed MRF-EPI method provides fast and accurate T 1 and T2∗ quantification. This approach offers a rapid supplement to the non-Cartesian MRF portfolio, with potentially increased usability and robustness. Magn Reson Med 78:1724-1733, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  9. Combined use of spin-echo and gradient-echo MR-imaging in cervical disk disease

    Energy Technology Data Exchange (ETDEWEB)

    Neuhold, A.; Stiskal, M.; Platzer, C. (Krankenanstalt Rudolfinerhaus, Vienna (Austria). Dept. of Diagnostic Imaging); Pernecky, G. (Krankenanstalt Rudolfinerhaus, Vienna (Austria). Neurosurgical Dept.); Brainin, M. (Landesnervenklinik Klosterneuburg-Gugging (Austria). Neurological Dept.)

    1991-10-01

    In a prospective study we compared the diagnostic value of combined gradient-echo (GE) and spin-echo (SE) MR imaging with cervical myelography in 30 patients with clinical signs and symptoms of cervical radiculopathy and/or myelopathy due to disk disease. Only patients who subsequently underwent surgery (anterior interbody approach) were included. By means of MRI the clinically relevant segment was identified in all cases, by means of myelography in all but two patients. Using both spin-echo (SE) and gradient-echo (GE) techniques it was possible to differentiate between bone tissue and disk material by MR in all but one. (orig./GDG).

  10. Combined use of spin-echo and gradient-echo MR-imaging in cervical disk disease

    International Nuclear Information System (INIS)

    Neuhold, A.; Stiskal, M.; Platzer, C.; Pernecky, G.; Brainin, M.

    1991-01-01

    In a prospective study we compared the diagnostic value of combined gradient-echo (GE) and spin-echo (SE) MR imaging with cervical myelography in 30 patients with clinical signs and symptoms of cervical radiculopathy and/or myelopathy due to disk disease. Only patients who subsequently underwent surgery (anterior interbody approach) were included. By means of MRI the clinically relevant segment was identified in all cases, by means of myelography in all but two patients. Using both spin-echo (SE) and gradient-echo (GE) techniques it was possible to differentiate between bone tissue and disk material by MR in all but one. (orig./GDG)

  11. Correlation of clinical and echo-cardiographic scores with blood ...

    African Journals Online (AJOL)

    Twenty four younger children (88%) and 29 older children (85%) had a high clinical score (severe CHF). Twenty one out of 23 younger children with high echo score (91%) had a high clinical score as well (p-value 0.001). In patients with RHD (all with a high clinical score), 81 % had a high echo score. (p-value 0.001).

  12. Theory and optical design of x-ray echo spectrometers

    Science.gov (United States)

    Shvyd'ko, Yuri

    2017-08-01

    X-ray echo spectroscopy, a space-domain counterpart of neutron spin echo, is a recently proposed inelastic x-ray scattering (IXS) technique. X-ray echo spectroscopy relies on imaging IXS spectra and does not require x-ray monochromatization. Due to this, the echo-type IXS spectrometers are broadband, and thus have a potential to simultaneously provide dramatically increased signal strength, reduced measurement times, and higher resolution compared to the traditional narrow-band scanning-type IXS spectrometers. The theory of x-ray echo spectrometers presented earlier [Yu. Shvyd'ko, Phys. Rev. Lett. 116, 080801 (2016), 10.1103/PhysRevLett.116.080801] is developed here further with a focus on questions of practical importance, which could facilitate optical design and assessment of the feasibility and performance of the echo spectrometers. Among others, the following questions are addressed: spectral resolution, refocusing condition, echo spectrometer tolerances, refocusing condition adjustment, effective beam size on the sample, spectral window of imaging and scanning range, impact of the secondary source size on the spectral resolution, angular dispersive optics, focusing and collimating optics, and detector's spatial resolution. Examples of optical designs and characteristics of echo spectrometers with 1-meV and 0.1-meV resolutions are presented.

  13. Fourier and wavelet domain denoising of active sonar echoes

    Science.gov (United States)

    Cable, Peter G.; Shah, Sheila; Butler, Gary

    2004-05-01

    Active sonar classification performance improves significantly when echo-to-background ratios increase above 10-15 dB. To achieve the improved echo waveform fidelity implied by increasing echo-to-background, preclassification processing methods are sought to improve echo waveform estimates. For this purpose a class of nonlinear techniques termed denoising, applied to efficient Hilbert space representations of transient signals, has been shown to yield nearly optimal estimation procedures for noise corrupted signals of unknown smoothness [D. L. Donoho and I. M. Johnstone, Biometrika 81 (1994)]. We have applied several versions of Fourier and wavelet domain denoising to noisy low-frequency target echoes and, for echoes near detection threshold, have demonstrated signal representation improvements equivalent to increases in echo-to-background of 4 dB. The theoretical foundations of denoising, including a new threshold algorithm, will be outlined and measures of performance for waveform estimation will be reviewed and discussed. The experimental methodology used and the results obtained for the test sonar echoes will be summarized and target classification implications of the results obtained from the analysis discussed. [Work supported by ONR.

  14. Hydrological remedial actions for polluted overburden dumps, spoils and landfills. Papers and posters; Wasserwirtschaftliche Sanierung von Bergbaukippen, Halden und Deponien. Vortraege und Posterbeitraege

    Energy Technology Data Exchange (ETDEWEB)

    Pohl, A. [ed.; Haefner, F.; Schmidt, J.; Merkel, B. [comps.

    2000-07-01

    This publication contains the papers and posters presented at the conference 'Hydrological remedial actions for polluted overburden dumps, spoils and landfills. 35 Papers have been recorded as separate citations in this database.

  15. The basics of neutron spin echo

    International Nuclear Information System (INIS)

    Farago, B.

    1999-01-01

    Until 1974 inelastic neutron scattering consisted of producing by some means a neutron beam of known speed and measuring the final speed of the neutrons after the scattering event. The smaller the energy change was, the better the neutron speed had to be defined. As the neutrons come form a reactor with an approximately Maxwell distribution, an infinitely good energy resolution can be achieved only at the expense of infinitely low count rate. This introduces a practical resolution limit around 0.1 μeV on back-scattering instruments. In 1972 F. Mezei discovered the method of Neutron Spin Echo. This method decouples the energy resolution from intensity loss. The basics of this method is presented. (author)

  16. Mock ECHO: A Simulation-Based Medical Education Method.

    Science.gov (United States)

    Fowler, Rebecca C; Katzman, Joanna G; Comerci, George D; Shelley, Brian M; Duhigg, Daniel; Olivas, Cynthia; Arnold, Thomas; Kalishman, Summers; Monnette, Rebecca; Arora, Sanjeev

    2018-04-16

    This study was designed to develop a deeper understanding of the learning and social processes that take place during the simulation-based medical education for practicing providers as part of the Project ECHO® model, known as Mock ECHO training. The ECHO model is utilized to expand access to care of common and complex diseases by supporting the education of primary care providers with an interprofessional team of specialists via videoconferencing networks. Mock ECHO trainings are conducted through a train the trainer model targeted at leaders replicating the ECHO model at their organizations. Trainers conduct simulated teleECHO clinics while participants gain skills to improve communication and self-efficacy. Three focus groups, conducted between May 2015 and January 2016 with a total of 26 participants, were deductively analyzed to identify common themes related to simulation-based medical education and interdisciplinary education. Principal themes generated from the analysis included (a) the role of empathy in community development, (b) the value of training tools as guides for learning, (c) Mock ECHO design components to optimize learning, (d) the role of interdisciplinary education to build community and improve care delivery, (e) improving care integration through collaboration, and (f) development of soft skills to facilitate learning. Mock ECHO trainings offer clinicians the freedom to learn in a noncritical environment while emphasizing real-time multidirectional feedback and encouraging knowledge and skill transfer. The success of the ECHO model depends on training interprofessional healthcare providers in behaviors needed to lead a teleECHO clinic and to collaborate in the educational process. While building a community of practice, Mock ECHO provides a safe opportunity for a diverse group of clinician experts to practice learned skills and receive feedback from coparticipants and facilitators.

  17. Spring and Its Global Echo: Quantitative Analysis

    Directory of Open Access Journals (Sweden)

    A. V. Korotayev

    2017-01-01

    Full Text Available It is shown that the Arab Spring acted as a trigger for a global wave of socio-political destabilization, which signifi cantly exceeded the scale of the Arab Spring itself and affected absolutely all world-system zones. Only in 2011 the growth of the global number of largescale anti-government demonstrations, riots and political strikes was to a high degree (although not entirely due to their growth in the Arab world. In the ensuing years, the Arab countries rather made a negative contribution to a very noticeable further increase in the global number of large-scale anti-government demonstrations, riots and general strikes (the global intensity of all these three important types of socio-political destabilization continued to grow despite the decline in the Arab world. Thus, for all these three important indicators of sociopolitical destabilization, the scale of the global echo of the Arab Spring has overshadowed the scale of the Arab Spring itself. Only as regards the fourth considered indicator (major terrorist attacks / guerrilla warfare the scale of the global echo for the entire period considered did not overshadow the scale of the Arab Spring (and, incidentally, «Winter» - and in 2014-2015 Arab countries continued to make a disproportionate contribution to the historically record global values of this sad indicator – global number of major terrorist attacks/ guerilla warfare. To conclude, triggered by the Arab Spring, the global wave of socio-political destabilization led after 2010 to a very signifi cant growth of socio-political instability in absolutely all World System zones. However, this global destabilization wave manifested itself in different World System zones in different ways and not completely synchronously.

  18. Room Geometry Estimation from Acoustic Echoes using Graph-Based Echo Labeling

    OpenAIRE

    Jager, Ingmar; Heusdens, R.; Gaubitch, N.D.; Dong, Min; Zheng, Thomas Fang

    2016-01-01

    A computer being able to estimate the geometry of a room could benefit applications such as auralization, robot navigation, virtual reality and teleconferencing. When estimating the geometry of a room using multiple microphones, the main challenge is to identify which reflections, or echoes, originate from the same wall and can, therefore, be modeled by a virtual source outside the room using the mirror image source model. In this paper we present a new and efficient method to disambiguate th...

  19. Water and materials balances of a spoil bank of an abandoned uranium mine in the Freital district, Sachsen

    International Nuclear Information System (INIS)

    Biehler, D.

    2000-01-01

    Sanitation of former uranium mines started immediately after uranium mining in East Germany was abandoned in 1990. In the case of shaft 1 of the Dresden-Gittersee mine, a multilayer mineral sealing system was decided. As required by the radiation protection authorities, the Wismut GmbH initiated a detailed hydrogeological expert's opinion including a forecast of the long-term effects of sealing on the basis of hydrogeological data and a material flow analysis for the spoil bank [de

  20. Subterranean clover enhances production of [open quote]Coastal[close quote] bermudagrass in the revegetation of lignite mine spoil

    Energy Technology Data Exchange (ETDEWEB)

    Harris, P.A. (Kansas Agriculture Experimental Station, Hays (United States)); Zuberer, D.A. (Texas A M Univ., College Station (United States))

    Lignite mine spoils in Texas are commonly revegetated with [open quote]Coastal[close quote] bermudagrass [Cynodon dactylon (L.) Pers.]. Legumes have been overseeded in bermudagrass in reclamation programs in Texas, but information regarding establishment and persistence in mine spoil is limited. A field study investigated the effects of fertilization and inoculation with Rhizobium spp. on subterranean clover (Trifolium subterraneum L.; subclover) establishment and production in mine spoil and to assess the effect of subclover on Coastal bermudagrass. Subclover seed was broadcast into a 6-mo-old bermudagrass sod in October 1986. Individual plots were fertilized, or left unfertilized at the beginning of each clover season (Sept.-Oct.); however, all plots were fertilized at the start of each grass season (April-May). Although native rhizobia was present in plots, inoculation with a commercial, multi-strain inoculant increases subclover forage production (100%) and total N and P yields of subclover. The overseeding of subclover into the bermuda grass sod increased grass production and total N and P yields later in the first year and in the second season. However, inoculation of subclover had little effect on subsequent grass production. There was an apparent positive benefit of P fertilization on subclover and bermudagrass production. The effect of subclover on grass production was apparent by the end of the first grass season, and it became even more evident in the second year. The results showed that subclover was established and maintained for at least two seasons in a bermudagrass sod on reclaimed lignite spoil, and that the clover benefited the subsequent grass crop when fertilized with P and K, apparently by providing extra [open quotes]fixed[close quotes] N for grass production. 22 refs., 5 tabs.

  1. Assessment of biochar and iron filing amendments for the remediation of a metal, arsenic and phenanthrene co-contaminated spoil

    International Nuclear Information System (INIS)

    Sneath, Helen E.; Hutchings, Tony R.; Leij, Frans A.A.M. de

    2013-01-01

    Sites contaminated with mixtures of metals, metalloids and organics are difficult to remediate as each contaminant type may require a different treatment. Biochar, with high metal sorption capacity, used singly and in combination with iron filings, is investigated in microcosm trials to immobilise metal(loid)s within a contaminated spoil, thereby enabling revegetation and degradation of organic pollutants. A mine spoil, contaminated with heavy metals, arsenic and spiked with phenanthrene was treated with either 1%w/w biochar, 5%w/w iron or their combination, enhancing phenanthrene degradation by 44–65%. Biochar treatment reduced Cu leaching and enabled sunflower growth, but had no significant effect on As mobility. Iron treatment reduced Cu and As leaching but negatively impacted soil structure and released high levels of Fe causing sunflower plant mortality. The combined treatment reduced both Cu and As leaching and enabled sunflower growth suggesting this could be a useful approach for treating co-contaminated sites. -- Highlights: ► 56 day microcosm trials examine biochar for remediation of co-contaminated sites. ► Biochar reduces leachable Cu concentrations but phytotoxicity remains. ► Iron filings are investigated as a co-amendment with biochar to reduce As leaching. ► Removal of metal toxicity stimulates phenanthrene degradation. ► Biochar could enable revegetation of contaminated sites. -- Biochar and iron filings incorporated into contaminated spoils reduce Cu and As leaching and stimulate phenanthrene degradation, but do not prevent phytotoxicity to sunflowers

  2. Noncontrast peripheral MRA with spiral echo train imaging.

    Science.gov (United States)

    Fielden, Samuel W; Mugler, John P; Hagspiel, Klaus D; Norton, Patrick T; Kramer, Christopher M; Meyer, Craig H

    2015-03-01

    To develop a spin echo train sequence with spiral readout gradients with improved artery-vein contrast for noncontrast angiography. Venous T2 becomes shorter as the echo spacing is increased in echo train sequences, improving contrast. Spiral acquisitions, due to their data collection efficiency, facilitate long echo spacings without increasing scan times. Bloch equation simulations were performed to determine optimal sequence parameters, and the sequence was applied in five volunteers. In two volunteers, the sequence was performed with a range of echo times and echo spacings to compare with the theoretical contrast behavior. A Cartesian version of the sequence was used to compare contrast appearance with the spiral sequence. Additionally, spiral parallel imaging was optionally used to improve image resolution. In vivo, artery-vein contrast properties followed the general shape predicted by simulations, and good results were obtained in all stations. Compared with a Cartesian implementation, the spiral sequence had superior artery-vein contrast, better spatial resolution (1.2 mm(2) versus 1.5 mm(2) ), and was acquired in less time (1.4 min versus 7.5 min). The spiral spin echo train sequence can be used for flow-independent angiography to generate three-dimensional angiograms of the periphery quickly and without the use of contrast agents. © 2014 Wiley Periodicals, Inc.

  3. Optimized three-dimensional fast-spin-echo MRI.

    Science.gov (United States)

    Mugler, John P

    2014-04-01

    Spin-echo-based acquisitions are the workhorse of clinical MRI because they provide a variety of useful image contrasts and are resistant to image artifacts from radio-frequency or static field inhomogeneity. Three-dimensional (3D) acquisitions provide datasets that can be retrospectively reformatted for viewing in freely selectable orientations, and are thus advantageous for evaluating the complex anatomy associated with many clinical applications of MRI. Historically, however, 3D spin-echo-based acquisitions have not played a significant role in clinical MRI due to unacceptably long acquisition times or image artifacts associated with details of the acquisition method. Recently, optimized forms of 3D fast/turbo spin-echo imaging have become available from several MR-equipment manufacturers (for example, CUBE [GE], SPACE [Siemens], and VISTA [Philips]). Through specific design strategies and optimization, including short non-spatially selective radio-frequency pulses to significantly shorten the echo spacing and variable flip angles for the refocusing radio-frequency pulses to suppress blurring or considerably lengthen the useable duration of the spin-echo train, these techniques permit single-slab 3D imaging of sizeable volumes in clinically acceptable acquisition times. These optimized fast/turbo spin-echo pulse sequences provide a robust and flexible approach for 3D spin-echo-based imaging with a broad range of clinical applications. Copyright © 2014 Wiley Periodicals, Inc.

  4. A comparison of multi-echo spin-echo and triple-echo steady-state T2 mapping for in vivo evaluation of articular cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Juras, Vladimir; Szomolanyi, Pavol [Medical University of Vienna, High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Institute of Measurement Science, Department of Imaging Methods, Bratislava (Slovakia); Bohndorf, Klaus; Kronnerwetter, Claudia; Hager, Benedikt; Zbyn, Stefan [Medical University of Vienna, High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Heule, Rahel; Bieri, Oliver [University of Basel Hospital, Division of Radiological Physics, Department of Radiology, Basel (Switzerland); Trattnig, Siegfried [Medical University of Vienna, High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna (Austria); Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Austrian Cluster for Tissue Regeneration, Vienna (Austria)

    2016-06-15

    To assess the clinical relevance of T{sub 2} relaxation times, measured by 3D triple-echo steady-state (3D-TESS), in knee articular cartilage compared to conventional multi-echo spin-echo T{sub 2}-mapping. Thirteen volunteers and ten patients with focal cartilage lesions were included in this prospective study. All subjects underwent 3-Tesla MRI consisting of a multi-echo multi-slice spin-echo sequence (CPMG) as a reference method for T{sub 2} mapping, and 3D TESS with the same geometry settings, but variable acquisition times: standard (TESSs 4:35min) and quick (TESSq 2:05min). T{sub 2} values were compared in six different regions in the femoral and tibial cartilage using a Wilcoxon signed ranks test and the Pearson correlation coefficient (r). The local ethics committee approved this study, and all participants gave written informed consent. The mean quantitative T{sub 2} values measured by CPMG (mean: 46±9ms) in volunteers were significantly higher compared to those measured with TESS (mean: 31±5ms) in all regions. Both methods performed similarly in patients, but CPMG provided a slightly higher difference between lesions and native cartilage (CPMG: 90ms→61ms [31%],p=0.0125;TESS 32ms→24ms [24%],p=0.0839). 3D-TESS provides results similar to those of a conventional multi-echo spin-echo sequence with many benefits, such as shortening of total acquisition time and insensitivity to B{sub 1} and B{sub 0} changes. (orig.)

  5. A comparison of multi-echo spin-echo and triple-echo steady-state T2 mapping for in vivo evaluation of articular cartilage

    International Nuclear Information System (INIS)

    Juras, Vladimir; Szomolanyi, Pavol; Bohndorf, Klaus; Kronnerwetter, Claudia; Hager, Benedikt; Zbyn, Stefan; Heule, Rahel; Bieri, Oliver; Trattnig, Siegfried

    2016-01-01

    To assess the clinical relevance of T 2 relaxation times, measured by 3D triple-echo steady-state (3D-TESS), in knee articular cartilage compared to conventional multi-echo spin-echo T 2 -mapping. Thirteen volunteers and ten patients with focal cartilage lesions were included in this prospective study. All subjects underwent 3-Tesla MRI consisting of a multi-echo multi-slice spin-echo sequence (CPMG) as a reference method for T 2 mapping, and 3D TESS with the same geometry settings, but variable acquisition times: standard (TESSs 4:35min) and quick (TESSq 2:05min). T 2 values were compared in six different regions in the femoral and tibial cartilage using a Wilcoxon signed ranks test and the Pearson correlation coefficient (r). The local ethics committee approved this study, and all participants gave written informed consent. The mean quantitative T 2 values measured by CPMG (mean: 46±9ms) in volunteers were significantly higher compared to those measured with TESS (mean: 31±5ms) in all regions. Both methods performed similarly in patients, but CPMG provided a slightly higher difference between lesions and native cartilage (CPMG: 90ms→61ms [31%],p=0.0125;TESS 32ms→24ms [24%],p=0.0839). 3D-TESS provides results similar to those of a conventional multi-echo spin-echo sequence with many benefits, such as shortening of total acquisition time and insensitivity to B 1 and B 0 changes. (orig.)

  6. A systematic investigation into the extraction of aluminum from coal spoil through kaolinite.

    Science.gov (United States)

    Qiao, X C; Si, P; Yu, J G

    2008-11-15

    This research has applied kaolin and active carbon (AC) to the investigation of the recovery of aluminum from coal spoil (CS). The kaolin, AC-containing kaolin mixture, and CS have been calcined at 500, 600, 700, 800, and 900 degrees C for 15, 30, 60, and 120 min. The transformation of kaolinite and aluminum extraction that occurred in each calcined sample have been characterized using XRD, TG, IR, and hydrochloric acid leaching methods. The dehydroxylation of kaolinite and the decomposition of metakaolin were influenced by thermal treatment temperature and time. The metakaolin had kept a portion of OH- in its structure until it was calcined at a temperature of 800 degrees C. Under 60 min treatment, new SiO2 phase was able to be formed at 500 degrees C, kaolinite was totally converted to metakaolin at 600 degrees C, and the SiO2 rejoined the reaction at 800 degrees C. The decompositions of CS were similar to those of kaolin mixture containing 20 wt % AC (MKC). The combustion of combustible matter accelerated the decomposition of kaolinite in the CS and MKC. Higher AC content led to lower aluminum extraction. The treatment at 600 degrees C was optimal for both CS and MKC.

  7. Response surface optimization of biosurfactant produced by Pseudomonas aeruginosa MA01 isolated from spoiled apples.

    Science.gov (United States)

    Abbasi, Habib; Sharafi, Hakimeh; Alidost, Leila; Bodagh, Atefe; Zahiri, Hossein Shahbani; Noghabi, Kambiz Akbari

    2013-01-01

    A potent biosurfactant-producing bacterial strain isolated from spoiled apples was identified by 16S rRNA as Pseudomonas aeruginosa MA01. Compositional analysis revealed that the extracted biosurfactant was composed of high percentages of lipid (66%, w/w) and carbohydrate (32%, w/w). The surface tension of pure water decreased gradually with increasing biosurfactant concentration to 32.5 mN m(-1) with critical micelle concentration (CMC) value of 10.1 mg L(-1). The Fourier transform infrared spectrum of extracted biosurfactant confirmed the glycolipid nature of this natural product. Response surface methodology (RSM) was employed to optimize the biosynthesis medium for the production of MA01 biosurfactant. Nineteen carbon sources and 11 nitrogen sources were examined, with soybean oil and sodium nitrate being the most effective carbon and nitrogen sources on biosurfactant production, respectively. Among the organic nitrogen sources examined, yeast extract was necessary as a complementary nitrogen source for high production yield. Biosurfactant production at the optimum value of fermentation processing factor (15.68 g/L) was 29.5% higher than the biosurfactant concentration obtained before the RSM optimization (12.1 g/L). A central composite design algorithm was used to optimize the levels of key medium components, and it was concluded that two stages of optimization using RSM could increase biosurfactant production by 1.46 times, as compared to the values obtained before optimization.

  8. Identifying yeast isolated from spoiled peach puree and assessment of its batch culture for invertase production

    Directory of Open Access Journals (Sweden)

    Marcela Vega FERREIRA

    Full Text Available Abstract The identification of yeasts isolated from spoiled Jubileu peach puree using the API 20C AUX method and a commercial yeast as witness were studied. Subsequently, the yeast’s growth potential using two batch culture treatments were performed to evaluate number of colonies (N, reducing sugar concentration (RS, free-invertase (FI, and culture-invertase activity (CI. Stock cultures were maintained on potato dextrose agar (PDA slants at 4 °C and pH 5 for later use for batch-culture (150 rpm at 30°C for 24 h, then they were stored at 4 °C for subsequent invertase extraction. The FI extract was obtained using NaHCO3 as autolysis agent, and CI activity was determined on the supernatant after batch-cultured centrifugation. The activity was followed by an increase in absorbance at 490 nm using the acid 3,5-DNS method with glucose standard. Of the four yeasts identified, Saccharomyces cerevisiae was chosen for legal reasons. It showed logarithmic growth up to 18 h of fermentation with positive correlation CI activity and inverse with RS. FI showed greater activity by the end of the log phase and an inverse correlation with CI activity. Finally, it was concluded that treatment “A” is more effective than “B” to produce invertase (EC 3.2.1.26.

  9. Lead Tolerance and Accumulation in Hirschfeldia incana, a Mediterranean Brassicaceae from Metalliferous Mine Spoils

    Science.gov (United States)

    Auguy, Florence; Fahr, Mouna; Moulin, Patricia; Brugel, Anaïs; Laplaze, Laurent; Mzibri, Mohamed El; Filali-Maltouf, Abdelkarim; Doumas, Patrick; Smouni, Abdelaziz

    2013-01-01

    Lead is a heavy metal of particular concern with respect to environmental quality and health. The lack of plant species that accumulate and tolerate Pb is a limiting factor to understand the molecular mechanisms involved in Pb tolerance. In this study we identified Hirschfeldia incana, a Brassicaceae collected from metalliferous mine spoils in Morocco, as a Pb accumulator plant. H. incana exhibited high Pb accumulation in mine soils and in hydroponic cultures. Major Pb accumulation occurred in the roots and a part of Pb translocated from the roots to the shoots, even to the siliques. These findings demonstrated that H. incana is a Pb accumulator species. The expression of several candidate genes after Pb-exposure was measured by quantitative PCR and two of them, HiHMA4 and HiMT2a, coding respectively for a P1B-type ATPase and a metallothionein, were particularly induced by Pb-exposure in both roots and leaves. The functional characterization of HiHMA4 and HiMT2a was achieved using Arabidopsis T-DNA insertional mutants. Pb content and primary root growth analysis confirmed the role of these two genes in Pb tolerance and accumulation. H. incana could be considered as a good experimental model to identify genes involved in lead tolerance and accumulation in plants. PMID:23667449

  10. Application of fast BLMS algorithm in acoustic echo cancellation

    Science.gov (United States)

    Zhao, Yue; Li, Nian Q.

    2013-03-01

    The acoustic echo path is usually very long and ranges from several hundreds to few thousands of taps. Frequency domain adaptive filter provides a solution to acoustic echo cancellation by means of resulting a significant reduction in the computational burden. In this paper, fast BLMS (Block Least-Mean-Square) algorithm in frequency domain is realized by using fast FFT technology. The adaptation of filter parameters is actually performed in the frequency domain. The proposed algorithm can ensure convergence with high speed and reduce computational complexity. Simulation results indicate that the algorithm demonstrates good performance for acoustic echo cancellation in communication systems.

  11. The role of 3D volumetric MR sequences in diagnosing intraventricular neurocysticercosis: preliminar results

    Directory of Open Access Journals (Sweden)

    Francisco Edward Frota Mont'Alverne Filho

    2011-02-01

    Full Text Available OBJECTIVE: The purpose of this paper was to investigate the role of two three-dimensional magnetic resonance (MRI sequences: enhanced spoiled gradient recalled echo (SPGR, and fast imaging employing steady-state acquisition (FIESTA in the evaluation of intraventricular neurocysticercosis cysts and scolices. METHOD: Seven neurocysticercosis patients suspected of presenting intraventricular lesions were evaluated by magnetic resonance imaging using enhanced SPGR, and FIESTA. RESULTS: Enhanced SPGR detected eight cystic lesions, with scolices in four. Contrast enhancement was observed in three cysts. FIESTA also detected eight cystic lesions with the presence of scolices in seven of those cystic lesions. Four patients presented parenchymal involvement, while the remaining three presented the racemose form. CONCLUSION: FIESTA and SPGR are sequences that can detect intraventricular cysts of neurocysticercosis, and FIESTA also is good for the detection of the scolex. Considering this information we suggest that FIESTA and SPGR should be included in the MRI protocol for the investigation of intraventricular neurocysticercosis.

  12. [Stress echo and valvular heart disease].

    Science.gov (United States)

    Monin, J L

    2005-06-01

    Stress echo has already been validated in some forms of valvular heart disease, especially in calcific aortic stenosis with low cardiac output and dynamic mitral regurgitation (MR) of valvular heart disease. Stress Doppler haemodynamics is a term used to differentiate these new indications from that of segmental wall analysis of the left atrium in ischaemic heart disease. In calcific aortic stenosis with low output, the haemodynamics with low dose dobutamine allows assessment of the real severity of the aortic stenosis and identification of the rare cases with mild stenosis: the principal indication remains the assessment of operative risk and long-term prognosis by the study of left ventricular contractile reserve. In cases of ischaemic left ventricular systolic dysfunction, the presence of mild mitral regurgitation (regurgitant surface area >20 mm2 at rest) is a poor prognostic factor. The dynamic character of mitral regurgitation is related to left ventricular remodelling which leads to deformation of the valvular apparatus (mitral tenting). Dynamic mitral regurgitation (regurgitant orifice area >13 mm2 on exercise) is a powerful prognostic factor, the role of which has recently been demonstrated in the genesis of acute pulmonary oedema. the other indications of stress haemodynamics are under validation, mainly the assessment of exercise capacity and valvular compliance in mitral stenosis or asymptomatic aortic stenosis.

  13. Geomagnetic control of polar mesosphere summer echoes

    Directory of Open Access Journals (Sweden)

    J. Bremer

    2000-02-01

    Full Text Available Using observations with the ALOMAR SOUSY radar near Andenes (69.3°N, 16.0°E from 1994 until 1997 polar mesosphere summer echoes (PMSE have been investigated in dependence on geomagnetic K indices derived at the Auroral Observatory Tromsø (69.66°N, 18.94°E. During night-time and morning hours a significant correlation between the signal-to-noise ratio (SNR of the radar results and the geomagnetic K indices could be detected with a maximum correlation near midnight. The correlation becomes markedly smaller in the afternoon and early evening hours with a minimum near 17 UT. This diurnal variation is in reasonable agreement with riometer absorption at Ivalo (68.55°N, 27.28°E and can be explained by the diurnal variation of ionization due to precipitating high energetic particles. Therefore, a part of the diurnal PMSE variation is caused by this particle precipitation. The variability of the solar EUV variation, however, has no significant influence on the PMSE during the observation period.Keywords: Ionosphere (auroral ionosphere - Magnetospheric physics (energetic particles, precipitating - Radio science (remote sensing

  14. Geomagnetic control of polar mesosphere summer echoes

    Directory of Open Access Journals (Sweden)

    J. Bremer

    Full Text Available Using observations with the ALOMAR SOUSY radar near Andenes (69.3°N, 16.0°E from 1994 until 1997 polar mesosphere summer echoes (PMSE have been investigated in dependence on geomagnetic K indices derived at the Auroral Observatory Tromsø (69.66°N, 18.94°E. During night-time and morning hours a significant correlation between the signal-to-noise ratio (SNR of the radar results and the geomagnetic K indices could be detected with a maximum correlation near midnight. The correlation becomes markedly smaller in the afternoon and early evening hours with a minimum near 17 UT. This diurnal variation is in reasonable agreement with riometer absorption at Ivalo (68.55°N, 27.28°E and can be explained by the diurnal variation of ionization due to precipitating high energetic particles. Therefore, a part of the diurnal PMSE variation is caused by this particle precipitation. The variability of the solar EUV variation, however, has no significant influence on the PMSE during the observation period.

    Keywords: Ionosphere (auroral ionosphere - Magnetospheric physics (energetic particles, precipitating - Radio science (remote sensing

  15. Book review: Musical echoes: South African women thinking in jazz ...

    African Journals Online (AJOL)

    Abstract. Title: Musical echoes: South African women thinking in jazz. Author: Muller, Carol and Sathima, Bea Benjamin. Publisher: Duke University Press. Publication year: 2011. ISBN 978-0-8223-4914-3 ...

  16. The architecture of dynamic reservoir in the echo state network

    Science.gov (United States)

    Cui, Hongyan; Liu, Xiang; Li, Lixiang

    2012-09-01

    Echo state network (ESN) has recently attracted increasing interests because of its superior capability in modeling nonlinear dynamic systems. In the conventional echo state network model, its dynamic reservoir (DR) has a random and sparse topology, which is far from the real biological neural networks from both structural and functional perspectives. We hereby propose three novel types of echo state networks with new dynamic reservoir topologies based on complex network theory, i.e., with a small-world topology, a scale-free topology, and a mixture of small-world and scale-free topologies, respectively. We then analyze the relationship between the dynamic reservoir structure and its prediction capability. We utilize two commonly used time series to evaluate the prediction performance of the three proposed echo state networks and compare them to the conventional model. We also use independent and identically distributed time series to analyze the short-term memory and prediction precision of these echo state networks. Furthermore, we study the ratio of scale-free topology and the small-world topology in the mixed-topology network, and examine its influence on the performance of the echo state networks. Our simulation results show that the proposed echo state network models have better prediction capabilities, a wider spectral radius, but retain almost the same short-term memory capacity as compared to the conventional echo state network model. We also find that the smaller the ratio of the scale-free topology over the small-world topology, the better the memory capacities.

  17. Criminal Enforcement Case Report Help | ECHO | US EPA

    Science.gov (United States)

    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  18. DW_Dashboard_CalendarView.png | ECHO | US EPA

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  9. Water Pollution Search Criteria Help | ECHO | US EPA

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  11. Water Quality Indicators Data Review | ECHO | US EPA

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

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    ECHO, Enforcement and Compliance History Online, provides compliance and enforcement information for approximately 800,000 EPA-regulated facilities nationwide. ECHO includes permit, inspection, violation, enforcement action, and penalty information about facilities regulated under the Clean Air Act (CAA) Stationary Source Program, Clean Water Act (CWA) National Pollutant Elimination Discharge System (NPDES), and/or Resource Conservation and Recovery Act (RCRA). Information also is provided on surrounding demographics when available.

  13. Significance-aware filtering for nonlinear acoustic echo cancellation

    Science.gov (United States)

    Hofmann, Christian; Huemmer, Christian; Guenther, Michael; Kellermann, Walter

    2016-12-01

    This article summarizes and extends the recently proposed concept of Significance-Aware (SA) filtering for nonlinear acoustic echo cancellation. The core idea of SA filtering is to decompose the estimation of the nonlinear echo path into beneficially interacting subsystems, each of which can be adapted with high computational efficiency. The previously proposed SA Hammerstein Group Models (SA-HGMs) decompose the nonlinear acoustic echo path into a direct-path part, modeled by a Hammerstein Group Model (HGM) and a complementary part, modeled by a very efficient Hammerstein model. In this article, we furthermore propose a novel Equalization-based SA (ESA) structure, where the echo path is equalized by a linear filter to allow for an estimation of the loudspeaker nonlinearities by very small and efficient models. Additionally, we provide a novel in-depth analysis of the computational complexity of the previously proposed SA and the novel ESA filters and compare both SA filtering approaches to each other, to adaptive HGMs, and to linear filters, where fast partitioned-block frequency-domain realizations of the competing filter structures are considered. Finally, the echo reduction performance of the proposed SA filtering approaches is verified using real recordings from a commercially available smartphone. Beyond the scope of previous publications on SA-HGMs, the ability of the SA filters to generalize for double-talk situations is explicitly considered as well. The low complexity as well as the good echo reduction performance of both SA filters illustrate the potential of SA filtering in practice.

  14. Improved MRI thermometry with multiple-echo spirals.

    Science.gov (United States)

    Marx, Michael; Butts Pauly, Kim

    2016-09-01

    Low-bandwidth PRF shift thermometry is used to guide HIFU ablation treatments. Low sampling bandwidth is needed for high signal-to-noise ratio with short acquisition times, but can lead to off-resonance artifacts. In this work, improved multiple-echo thermometry is presented that allows for high bandwidth and reduced artifacts. It is also demonstrated with spiral sampling, to improve the trade-off between resolution, speed, and measurement precision. Four multiple-echo thermometry sequences were tested in vivo, one using two-dimensional Fourier transform (2DFT) sampling and three using spirals. The spiral sequences were individually optimized for resolution, for speed, and for precision. Multifrequency reconstruction was used to correct for off-resonance spiral artifacts. Additionally, two different multiecho temperature reconstructions were compared. Weighted combination of per-echo phase differences gave significantly better precision than least squares off-resonance estimation. Multiple-echo 2DFT sequence obtained precision similar to single-echo 2DFT, while greatly increasing sampling bandwidth. The multiecho spiral acquisitions achieved 2× better resolution, 2.9× better uncertainty, or 3.4× faster acquisition time, without negatively impacting the other two design parameters as compared to single-echo 2DFT. Multiecho spiral thermometry greatly improves the capabilities of temperature monitoring, and could improve transcranial treatment monitoring capabilities. Magn Reson Med 76:747-756, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  15. Wavelets for ultrasonic echo identification in aircraft fuel tanks

    Science.gov (United States)

    Sadok, Mokhtar

    2002-03-01

    Recently, Goodrich Corp.- Fuels and Utility systems Division, has launched a research effort to investigate various sensing and computing techniques to gauge fuel in commercial and military aircrafts. Ultrasonics are among other techniques that were tested for such purpose. Generally, in ultrasonic fuel measurement systems, a transducer is excited to create sonic bursts into fuel and measure reflected echo off the fuel surface. A fixed target or pin is usually disposed at a fixed and predetermined distance from the ultrasonic transducer within the tank so as to compute the speed of sound through across fuel in the tank. Knowing the speed of sound in fuel and being able to measure the round trip time from when an ultrasonic burst is generated until its reflected off the fuel surface, the fuel height may be calculated. With a priori knowledge of the tank geometry, the fuel quantity can be estimated. This measurement process seems straightforward. A problem however is being able to discriminate between echoes reflected off various objects within the tank. In particular, it is crucial to discriminate among echoes reflected off various objects within the tank. In particular, it is crucial to discriminate among echoes reflected off the fuel surface and echoes reflected off other object withhin the tank, like the fixed target or tank sides. This paper presents a discrimination method based on wavelets to assign various ultrasonic echoes to their appropriate reflective surfaces.

  16. Velocities of Auroral Coherent Echoes At 12 and 144 Mhz

    Science.gov (United States)

    Koustov, A. V.; Danskin, D. W.; Makarevitch, R. A.; Uspensky, M. V.; Janhunen, P.; Nishitani, N.; Nozawa, N.; Lester, M.; Milan, S.

    Two Doppler coherent radar systems are currently working at Hankasalmi, Finland, the STARE and CUTLASS radars operating at 144 MHz and 12 MHz, respectively. The STARE beam 3 is nearly co-located with the CUTLASS beam 5 providing an opportunity for echo velocity comparison along the same direction but at significantly different radar frequencies. In this study we consider one event when STARE radar echoes are detected t the same ranges as CUTLASS radar echoes. The observations are complemented by EISCAT measurements of the ionospheric electric field and elec- tron density behavior at one range of 900 km. Two separate situations are studied; for the first one, CUTLASS observed F-region echoes (including the range of the EIS- CAT measurements) while for the second one CUTLASS observed E-region echoes. In both cases STARE E-region measurements were available. We show that F-region CUTLASS velocities agree well with the convection component along the CUTLASS radar beam while STARE velocities are sometimes smaller by a factor of 2-3. For the second case, STARE velocities are found to be either smaller or larger than CUTLASS velocities, depending on range. Plasma physics of E- and F-region irregularities is dis- cussed in attempt to explain inferred relationship between various velocities. Special attention is paid to ionospheric refraction that is important for the detection of 12-MHz echoes.

  17. Wavelet-LMS algorithm-based echo cancellers

    Science.gov (United States)

    Seetharaman, Lalith K.; Rao, Sathyanarayana S.

    2002-12-01

    This paper presents Echo Cancellers based on the Wavelet-LMS Algorithm. The performance of the Least Mean Square Algorithm in Wavelet transform domain is observed and its application in Echo cancellation is analyzed. The Widrow-Hoff Least Mean Square Algorithm is most widely used algorithm for Adaptive filters that function as Echo Cancellers. The present day communication signals are widely non-stationary in nature and some errors crop up when Least Mean Square Algorithm is used for the Echo Cancellers handling such signals. The analysis of non-stationary signals often involves a compromise between how well transitions or discontinuities can be located. The multi-scale or multi-resolution of signal analysis, which is the essence of wavelet transform, makes Wavelets popular in non-stationary signal analysis. In this paper, we present a Wavelet-LMS algorithm wherein the wavelet coefficients of a signal are modified adaptively using the Least Mean Square Algorithm and then reconstructed to give an Echo-free signal. The Echo Canceller based on this Algorithm is found to have a better convergence and a comparatively lesser MSE (Mean Square error).

  18. Imaging of the brain using the fast-spin-echo and gradient-spin-echo techniques

    Energy Technology Data Exchange (ETDEWEB)

    Umek, W.; Ba-Ssalamah, A.; Prokesch, R. [Department of Radiology, University of Vienna (Austria); Mallek, R.; Heimberger, K. [Division of Neuroradiology, University of Vienna (Austria); Hittmair, K. [Department of Radiology, University of Vienna (Austria)]|[Department of Radiology, AKH Linz (Austria)

    1998-03-27

    The aim of our study was to compare gradient-spin-echo (GRASE) to fast-spin-echo (FSE) sequences for fast T2-weighted MR imaging of the brain. Thirty-one patients with high-signal-intensity lesions on T2-weighted images were examined on a 1.5-T MR system. The FSE and GRASE sequences with identical sequence parameters were obtained and compared side by side. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, signal-to-noise, contrast-to-noise, and contrast ratios and were determined. The FSE technique demonstrated more lesions than GRASE and with generally better conspicuity. Smaller lesions in particular were better demonstrated on FSE because of lower image noise and slightly weaker image artifacts. Gray-white differentiation was better on FSE. Ferritin and hemosiderin depositions appeared darker on GRASE, which resulted in better contrast. Fatty tissue was less bright on GRASE. With current standard hardware equipment, the FSE technique seems preferable to GRASE for fast T2-weighted routine MR imaging of the brain. For the assessment of hemosiderin or ferritin depositions, GRASE might be considered. (orig.) With 3 figs., 4 tabs., 29 refs.

  19. Dynamic MR imaging of the temporomandibular joint arthrosis using spoiled GRASS sequence

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Shigeaki; Hamamoto, Sadatoshi; Kawano, Kazunori (Kagoshima Univ. (Japan). Dental School) (and others)

    1994-07-01

    The purpose of this study was to quantitatively evaluate contrast enhancement effects of the posterior disk attachment in the temporomandibular joint arthrosis using dynamic MRI with bilateral surface coils. One hundred twenty-four temporomandibular joints in 96 symptomatic patients and 27 control subjects were examined with a spoiled GRASS pulse sequence (TR: 35 ms, TE: 8 ms, flip angle: 60deg). One sagittal scan was performed prior to injection, then 0.1 mmol/kg of Gd-DTPA was given as a rapid bolus injection, immediately after which scans were performed at 30 seconds intervals for a period of 5 minutes. Signal intensity (SI) was measured from the ROI of the posterior disk attachment region. The contrast enhancement effects may be calculated by SI ratio (SIR) = ( SI[sup post]-SI[sup pre])/SI[sup pre], where SI[sup post] and SI[sup pre] were the signal intensities after and before administration of contrast medium. The time intensity curve of SIR versus time after injection was obtained on each symptoms. Join pain group (85 joints) tended to show a rapid enhancement pattern, while control group (54 joints), joint sound or opening limitation group (39 joints), and asymptomatic group (68 joints) showed a relatively gradual enhancement pattern. The drop of SIR in four groups were hardly observed during examination. Mean peak SIR of control group, joint pain group, joint sound or opening limitation group, and asymptomatic group was 0.62[+-]0.24 (SD), 1.53[+-]0.69, 0.73[+-]0.38 and 0.78[+-]0.44 respectively. The mean SIR of pain group was significantly (P<0.001, t-test) higher than that of other groups. These results suggested that dynamic MRI of the temporomandibular joint may effectively depict the inflammatory changes of the posterior disk attachment. (author).

  20. Dynamic MR imaging of the temporomandibular joint arthrosis using spoiled GRASS sequence

    International Nuclear Information System (INIS)

    Suenaga, Shigeaki; Hamamoto, Sadatoshi; Kawano, Kazunori

    1994-01-01

    The purpose of this study was to quantitatively evaluate contrast enhancement effects of the posterior disk attachment in the temporomandibular joint arthrosis using dynamic MRI with bilateral surface coils. One hundred twenty-four temporomandibular joints in 96 symptomatic patients and 27 control subjects were examined with a spoiled GRASS pulse sequence (TR: 35 ms, TE: 8 ms, flip angle: 60deg). One sagittal scan was performed prior to injection, then 0.1 mmol/kg of Gd-DTPA was given as a rapid bolus injection, immediately after which scans were performed at 30 seconds intervals for a period of 5 minutes. Signal intensity (SI) was measured from the ROI of the posterior disk attachment region. The contrast enhancement effects may be calculated by SI ratio (SIR) = ( SI post -SI pre )/SI pre , where SI post and SI pre were the signal intensities after and before administration of contrast medium. The time intensity curve of SIR versus time after injection was obtained on each symptoms. Join pain group (85 joints) tended to show a rapid enhancement pattern, while control group (54 joints), joint sound or opening limitation group (39 joints), and asymptomatic group (68 joints) showed a relatively gradual enhancement pattern. The drop of SIR in four groups were hardly observed during examination. Mean peak SIR of control group, joint pain group, joint sound or opening limitation group, and asymptomatic group was 0.62±0.24 (SD), 1.53±0.69, 0.73±0.38 and 0.78±0.44 respectively. The mean SIR of pain group was significantly (P<0.001, t-test) higher than that of other groups. These results suggested that dynamic MRI of the temporomandibular joint may effectively depict the inflammatory changes of the posterior disk attachment. (author)

  1. Acetobacter aceti fast identification by Real Time PCR in spoiled wine samples

    Directory of Open Access Journals (Sweden)

    Attila Kántor

    2014-10-01

    Full Text Available Wine is a beverage that made from grape berries. However, without beneficial bacteria, we would not produce good wine. But very often wines contain acetic acid bacteria, which are undesirable in winemaking process. Acetic acid bacteria as known as a vinegar bacteria are Gram-negative, aerobic, rod-shaped and ubiquitous bacteria. This study was focused on species of acetic acid bacteria, specifically Acetobacter aceti that make spoilage in wine.The aim of our study was the identification of Acetobacter aceti in spoiled red wine samples, with plate dilution method on agar plates and using sensitive Real-time PCR (qPCR method. We cultivated Acetobacter aceti on GYC agar at 30°C, 48h. The one of main objective in the present work was the test fast, sensitive and reliable technique such as quantitative Real-time PCR and detecting the presence of Acetobacter aceti in wine samples with positive Acetobacteraceti control on amplification plot and melting curve. The next objective before  qPCR analysis was DNA extraction from wine samples incubated for one week at 28°C aerobically. We used five different red wine samples for this experiment: Alibernet 2013, Blaufränkisch 2013, Cabernet Sauvignon 2013, Dunaj 2012 and Saint-Laurent 2012. Next we extracted DNA from wine samples and from pure Acetobacter aceti CCM 3620T strain purchased from Czech collection of microorganisms in Brno. Susceptibility ofAcetobacter aceti was varied in different isolates from 102 to 107 CFU.mL-1. The number of Acetobacter cells on GYC medium ranged from 4.05 to 4.83log CFU.mL-1 in differentwine samples.The higher number of Acetobacter cells (4.83 log CFU.mL-1 was found in Cabernet Sauvignon 2013 wine.

  2. Coal Mining Spoil Heap Management as urban solid waste dump; Utilizacion de Escombreras de Carbon como Vertedero Controlado de Residuos Solidos Urbanos

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    In the coordinated project DISPOSAL OF SOLID RESIDUES FROM COAL it is included the project Coal Mining Spoil Heap Management as Urban Solid Waste Dump. The main target of this project consisted of determining the viability of using coal mining spoil heaps, as controlled dubbish dump of urban solid wastes. The working plan to achieve this objective was composed of the following stages: 1. Urban solid wastes characterization. 2. Methodology to be followed for the selection of coal mining spoil heaps as controlled dump of urban solid wastes. 2.1 Classification and preliminary assessment of the possibility of using spoil heaps as urban solid waste dumps (APT/NON APT). 2.2 Realization of geological, geotechnical, hydrogeological and environmental studies applied to the spoil heaps classified as APT. 2.3 Analysis of the compatibility of the mining activity with the urban solid wastes dumped on the spoil heap. 2.4 Analysis of the use of coal mining wastes in the rubbish dump operative life. 3. Extraction of conclusions. The works were focused in the Leon province. As result of the researches we obtained the following results and conclusions: In the areas studied, only two emplacements are optima to dump urban solid wastes; spoil heap n. 13. Roguera Mine (Cinera-Matallana) and the open pit mine n. 4, Las Chaviadas, in Villablino. The active spoil heap use as controlled rubbish dump can cause, if not managed adequately, several coperating and occupational problems to the mine and to the company that manages the urban solid wastes. The abandoned spoil heap utilisation is difficult due to the problems that would arise when conditioning the site to be use as rubbish dump. The use of abandoned open pit mines, as controlled rubbish dump is feasible if geological, geotechnical, hydrogeological and environmental studies support it. It's possible the use of the coal mining wastes in the different operatives phases of the controlled rubbish dump. The evaluation methodology

  3. Single echo acquisition MRI using RF encoding.

    Science.gov (United States)

    Wright, Steven M; McDougall, Mary Preston

    2009-11-01

    Encoding of spatial information in magnetic resonance imaging is conventionally accomplished by using magnetic field gradients. During gradient encoding, the position in k-space is determined by a time-integral of the gradient field, resulting in a limitation in imaging speed due to either gradient power or secondary effects such as peripheral nerve stimulation. Partial encoding of spatial information through the sensitivity patterns of an array of coils, known as parallel imaging, is widely used to accelerate the imaging, and is complementary to gradient encoding. This paper describes the one-dimensional limit of parallel imaging in which all spatial localization in one dimension is performed through encoding by the radiofrequency (RF) coil. Using a one-dimensional array of long and narrow parallel elements to localize the image information in one direction, an entire image is obtained from a single line of k-space, avoiding rapid or repeated manipulation of gradients. The technique, called single echo acquisition (SEA) imaging, is described, along with the need for a phase compensation gradient pulse to counteract the phase variation contained in the RF coil pattern which would otherwise cause signal cancellation in each imaging voxel. Image reconstruction and resolution enhancement methods compatible with the speed of the technique are discussed. MR movies at frame rates of 125 frames per second are demonstrated, illustrating the ability to monitor the evolution of transverse magnetization to steady state during an MR experiment as well as demonstrating the ability to image rapid motion. Because this technique, like all RF encoding approaches, relies on the inherent spatially varying pattern of the coil and is not a time-integral, it should enable new applications for MRI that were previously inaccessible due to speed constraints, and should be of interest as an approach to extending the limits of detection in MR imaging.

  4. Remedial Investigation Report on Bear Creek Valley Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 1, Main text

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-01

    This report on the BCV OU 2 at the Y-12 Plant, was prepared in accordance with requirements under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) for reporting the results of a site characterization for public review. It provides the Environmental Restoration Program with information about the results of the 1993 investigation. It includes information on risk assessments that have evaluated impacts to human health and the environment. Field activities included collection of subsurface soil samples, groundwater and surface water samples, and sediments and seep at the Rust Spoil Area (RSA), SY-200 Yard, and SA-1.

  5. Remedial Investigation Report on Bear Creek Valley Operable Unit 2 (Rust Spoil Area, Spoil Area 1, and SY-200 Yard) at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee. Volume 1, Main text

    International Nuclear Information System (INIS)

    1995-01-01

    This report on the BCV OU 2 at the Y-12 Plant, was prepared in accordance with requirements under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) for reporting the results of a site characterization for public review. It provides the Environmental Restoration Program with information about the results of the 1993 investigation. It includes information on risk assessments that have evaluated impacts to human health and the environment. Field activities included collection of subsurface soil samples, groundwater and surface water samples, and sediments and seep at the Rust Spoil Area (RSA), SY-200 Yard, and SA-1

  6. Chemical and isotopic tracing of underground water in relation with leaching of mine spoils, Nord-Pas-de-Calais Coal Basin (France)

    International Nuclear Information System (INIS)

    Denimal, S.; Tribovillard, N.; Meilliez, F.; Barbecot, F.; Dever, L.

    2001-01-01

    Coal mining activity in the Nord-Pas-de-Calais region (Northern France) has generated many mine spoils. The oxidation of the pyrite content of such coal shales and their leaching can be a source of sulfate pollution for the underlying chalk aquifer, i.e. the main drinking water resource of the region. Two sites of study have been retained: one in the free water table zone and the other in the confined water table zone. Samples from both mine spoils have been analyzed with respect to their carbon and sulfur content and a superficial leaching of these elements has been evidenced. Water has been sampled in piezometers and boreholes close to the mine spoils and also along natural flux lines. The use of sulfur isotopes as markers of the different sulfate sources has confirmed the spoils source but has permitted to identify another source in the second site which is the Tertiary gypsum-bearing Ostricourt sands. This study has shown also that in the confined water table zone, part of the exported sulfates is reduced. This bacterial reduction of sulfates is due to a joint leaching of both carbon and sulfur in the mine spoils. A self-purification phenomenon occurs when the chalk aquifer is confined beneath the Cenozoic cover. (J.S.)

  7. The impact of spin coupling signal loss on fat content characterization in multi-echo acquisitions with different echo spacing.

    Science.gov (United States)

    Nikiforaki, K; Manikis, G C; Boursianis, T; Marias, K; Karantanas, A; Maris, T G

    2017-05-01

    This study aimed to assess the effect of echo spacing in transverse magnetization (T2) signal decay of gel and fat (oil) samples. Additionally, we assess the feasibility of using spin coupling as a determinant of fat content. Phantoms of known T2 values, as well as vegetable oil phantoms, were scanned at 1.5T scanner with a multi echo FSE sequence of variable echo spacing above and below the empirical threshold of 20ms for echo train signal modulation (6.7, 13.6, 26.8, and 40ms). T2 values were calculated from monoexponential fitting of the data. Relative signal loss between the four acquisitions of different echo spacing was calculated. Agreement in the T2 values of water gel phantom was observed in all acquisitions as opposed to fat phantom (oil) samples. Relative differences in signal intensity between two successive sequences of different echo spacing on composite fat/water regions of interest was found to be linearly correlated to fat fraction of the ROI. The sample specific degree of signal loss that was observed between different fat samples (vegetable oils) can be attributed to the composition of each sample in J coupled fat components. Hence, spin coupling may be used as a determinant of fat content. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Bioavailability and microbial adaptation to elevated levels of uranium in an acid, organic topsoil forming on an old mine spoil

    International Nuclear Information System (INIS)

    Joner, E.J.; Munier-Lamy, C.; Gouget, B.

    2007-01-01

    An old mine spoil at a 19. century mining site with considerable residues of uranium (400-800 mg U/kg) was investigated with respect to U concentrations in soil and plants and tolerance to U in the soil microbial community in order to describe the bioavailability of U. Measurements of soil fractions representing water-soluble U, easily exchangeable U, and U bound to humidified organic matter showed that all fractions contained elevated concentrations of U. Plant U concentrations were only 10 times higher at the mine spoil site compared to the reference site (3 mg U/kg vs 0.3 mg U/kg), while the most easily available soil fractions contained 0.18 to 0.86 mg U/kg soil at the mine spoil. An eco-toxicity bioassay using incorporation of [ 3 H]thymidine into the indigenous microbial communities of the two soils in the presence of increasing U concentrations showed that microorganisms at the mining site were sensitive to U but also that they had acquired a substantial tolerance toward U (EC50, the effective concentration reducing activity by 50% of UO 2 -citrate was similar to 120 μM as compared to 30 μM in the reference soil). In the assay, more than 40% of the microbial activity was maintained in the presence of 1 mM UO 2 -citrate versus 3% in the reference soil. We conclude that U-enriched mining waste can contain sufficiently elevated concentrations of bio-available U to affect indigenous microorganisms and that bio-available U imposes a selection pressure that favors the development of a highly uranium-tolerant microbial community, while plant uptake of U remains low. (authors)

  9. Research on key technologies of LADAR echo signal simulator

    Science.gov (United States)

    Xu, Rui; Shi, Rui; Ye, Jiansen; Wang, Xin; Li, Zhuo

    2015-10-01

    LADAR echo signal simulator is one of the most significant components of hardware-in-the-loop (HWIL) simulation systems for LADAR, which is designed to simulate the LADAR return signal in laboratory conditions. The device can provide the laser echo signal of target and background for imaging LADAR systems to test whether it is of good performance. Some key technologies are investigated in this paper. Firstly, the 3D model of typical target is built, and transformed to the data of the target echo signal based on ranging equation and targets reflection characteristics. Then, system model and time series model of LADAR echo signal simulator are established. Some influential factors which could induce fixed delay error and random delay error on the simulated return signals are analyzed. In the simulation system, the signal propagating delay of circuits and the response time of pulsed lasers are belong to fixed delay error. The counting error of digital delay generator, the jitter of system clock and the desynchronized between trigger signal and clock signal are a part of random delay error. Furthermore, these system insertion delays are analyzed quantitatively, and the noisy data are obtained. The target echo signals are got by superimposing of the noisy data and the pure target echo signal. In order to overcome these disadvantageous factors, a method of adjusting the timing diagram of the simulation system is proposed. Finally, the simulated echo signals are processed by using a detection algorithm to complete the 3D model reconstruction of object. The simulation results reveal that the range resolution can be better than 8 cm.

  10. Comparative growth behaviour and leaf nutrient status of native trees planted on mine spoil with and without nutrient amendment

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.; Singh, J.S. [Banaras Hindu University, Varanasi (India). Dept. of Botany

    2001-07-01

    The effect of nutrient amendment on growth of nine indigenous tree species planted on coal mine spoil was studied. Greater growth in fertilized plots was accompanied by greater foliar N and P concentrations in all species. The response to fertilization varied among species and was greater in non-leguminous than in leguminous species. Furthermore, leguminous species exhibited higher growth rates compared to non-leguminous species. Acacia catechu, Dalbergia sissoo, Gmelina arborea and Azadirachta indica fitted the elastic similarity model of tree growth; whereas Pongamia pinnata and Phyllanthus emblica followed the constant stress model. Tectona grandis was the only species which fitted the geometric similarity model.

  11. Fast fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging of the brain: a comparison of multi-shot echo-planar and fast spin-echo techniques

    International Nuclear Information System (INIS)

    Sargent, M.A.; Poskitt, K.J.

    1997-01-01

    Purpose. To evaluate fast spin-echo and multi-shot echo-planar fluid-attenuated inversion recovery (FLAIR) sequences in paediatric brain imaging. Materials and methods. Matched images from 32 patients with suspected tumour or white matter disease were independently evaluated by two paediatric neuroradiologists. The observer preferences for image quality and lesion detection were analysed for differences between fast spin-echo FLAIR and multi-shot echo-planar FLAIR. Diagnostic quality was compared with that of fast spin-echo T2-weighted images. Results. Images of a diagnostic quality equivalent to that of fast spin-echo T2-weighted images were achieved with both FLAIR techniques. Grey and white matter differentiation and cerebrospinal fluid (CSF) nulling were significantly better on fast spin-echo FLAIR sequences. CSF flow artefact was reduced on multi-shot echo-planar FLAIR. There was no difference in lesion detection. Fast spin-echo FLAIR images were visually preferred at the expense of longer imaging time. Conclusion. Fast FLAIR techniques are complementary to fast spin-echo T2-weighted sequences in imaging of the paediatric brain. We find that the fast spin-echo FLAIR sequence is preferable to the multi-shot echo-planar technique. (orig.). With 5 figs., 2 tabs

  12. Single-shot echo-planar imaging with Nyquist ghost compensation: interleaved dual echo with acceleration (IDEA) echo-planar imaging (EPI).

    Science.gov (United States)

    Poser, Benedikt A; Barth, Markus; Goa, Pål-Erik; Deng, Weiran; Stenger, V Andrew

    2013-01-01

    Echo planar imaging (EPI) is most commonly used for blood oxygen level-dependent fMRI, owing to its sensitivity and acquisition speed. A major problem with EPI is Nyquist (N/2) ghosting, most notably at high field. EPI data are acquired under an oscillating readout gradient and hence vulnerable to gradient imperfections such as eddy current delays and off-resonance effects, as these cause inconsistencies between odd and even k-space lines after time reversal. We propose a straightforward and pragmatic method herein termed "interleaved dual echo with acceleration (IDEA) EPI": two k-spaces (echoes) are acquired under the positive and negative readout lobes, respectively, by performing phase encoding blips only before alternate readout gradients. From these two k-spaces, two almost entirely ghost free images per shot can be constructed, without need for phase correction. The doubled echo train length can be compensated by parallel imaging and/or partial Fourier acquisition. The two k-spaces can either be complex averaged during reconstruction, which results in near-perfect cancellation of residual phase errors, or reconstructed into separate images. We demonstrate the efficacy of IDEA EPI and show phantom and in vivo images at both 3 T and 7 T. Copyright © 2012 Wiley Periodicals, Inc.

  13. X-ray shout echoing through space

    Science.gov (United States)

    2004-01-01

    a flash of X-rays hi-res Size hi-res: 3991 Kb Credits: ESA, S. Vaughan (University of Leicester) EPIC camera shows the expanding rings caused by a flash of X-rays XMM-Newton's X-ray EPIC camera shows the expanding rings caused by a flash of X-rays scattered by dust in our Galaxy. The X-rays were produced by a powerful gamma-ray burst that took place on 3 December 2003. The slowly fading afterglow of the gamma-ray burst is at the centre of the expanding rings. Other, unrelated, X-ray sources can also be seen. The time since the gamma-ray explosion is shown in each panel in hours. At their largest size, the rings would appear in the sky about five times smaller than the full moon. a flash of X-rays hi-res Size hi-res: 2153 Kb Credits: ESA, S. Vaughan (University of Leicester) EPIC camera shows the expanding rings caused by a flash of X-rays (Please choose "hi-res" version for animation) XMM-Newton's X-ray EPIC camera shows the expanding rings caused by a flash of X-rays scattered by dust in our Galaxy. The X-rays were produced by a powerful gamma-ray burst that took place on 3 December 2003. The slowly fading afterglow of the gamma-ray burst is at the centre of the expanding rings. Other, unrelated, X-ray sources can also be seen. The time since the gamma-ray explosion is shown in each panel in seconds. At their largest size, the rings would appear in the sky about five times smaller than the full moon. This echo forms when the powerful radiation of a gamma-ray burst, coming from far away, crosses a slab of dust in our Galaxy and is scattered by it, like the beam of a lighthouse in clouds. Using the expanding rings to precisely pin-point the location of this dust, astronomers can identify places where new stars and planets are likely to form. On 3 December 2003 ESA's observatory, Integral, detected a burst of gamma rays, lasting about 30 seconds, from the direction of a distant galaxy. Within minutes of the detection, thanks to a sophisticated alert network, many

  14. E-region echo characteristics governed by auroral arc electrodynamics

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    Full Text Available Observations of a pair of auroral arc features by two imagers, one ground- and one space-based, allows the associated field-aligned current (FAC and electric field structure to be inferred. Simultaneous observations of HF radar echoes provide an insight into the irregularity-generating mechanisms. This is especially interesting for the E-region echoes observed, which form the focus of our analysis, and from which several conclusions can be drawn, summarized as follows. Latitudinal variations in echo characteristics are governed by the FAC and electric field background. Particularly sharp boundaries are found at the edges of auroral arcs. Within regions of auroral luminosity, echoes have Doppler shifts below the ion-acoustic speed and are proportional to the electric field, suggesting scatter from gradient drift waves. Regions of downward FAC are associated with mixed high and low Doppler shift echoes. The high Doppler shift component is greatly in excess of the ion-acoustic speed, but seems to be commensurate with the driving electric field. The low Doppler shift component appears to be much depressed below expectations.

    Key words. Ionosphere (ionospheric irregularities; electric fields and currents

  15. E-region echo characteristics governed by auroral arc electrodynamics

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    2003-07-01

    Full Text Available Observations of a pair of auroral arc features by two imagers, one ground- and one space-based, allows the associated field-aligned current (FAC and electric field structure to be inferred. Simultaneous observations of HF radar echoes provide an insight into the irregularity-generating mechanisms. This is especially interesting for the E-region echoes observed, which form the focus of our analysis, and from which several conclusions can be drawn, summarized as follows. Latitudinal variations in echo characteristics are governed by the FAC and electric field background. Particularly sharp boundaries are found at the edges of auroral arcs. Within regions of auroral luminosity, echoes have Doppler shifts below the ion-acoustic speed and are proportional to the electric field, suggesting scatter from gradient drift waves. Regions of downward FAC are associated with mixed high and low Doppler shift echoes. The high Doppler shift component is greatly in excess of the ion-acoustic speed, but seems to be commensurate with the driving electric field. The low Doppler shift component appears to be much depressed below expectations.Key words. Ionosphere (ionospheric irregularities; electric fields and currents

  16. Faraday rotation echo spectroscopy and detection of quantum fluctuations.

    Science.gov (United States)

    Chen, Shao-Wen; Liu, Ren-Bao

    2014-04-15

    Central spin decoherence is useful for detecting many-body physics in environments and moreover, the spin echo control can remove the effects of static thermal fluctuations so that the quantum fluctuations are revealed. The central spin decoherence approach, however, is feasible only in some special configurations and often requires uniform coupling between the central spin and individual spins in the baths, which are very challenging in experiments. Here, by making analogue between central spin decoherence and depolarization of photons, we propose a scheme of Faraday rotation echo spectroscopy (FRES) for studying quantum fluctuations in interacting spin systems. The echo control of the photon polarization is realized by flipping the polarization with a birefringence crystal. The FRES, similar to spin echo in magnetic resonance spectroscopy, can suppress the effects of the static magnetic fluctuations and therefore reveal dynamical magnetic fluctuations. We apply the scheme to a rare-earth compound LiHoF4 and calculate the echo signal, which is related to the quantum fluctuations of the system. We observe enhanced signals at the phase boundary. The FRES should be useful for studying quantum fluctuations in a broad range of spin systems, including cold atoms, quantum dots, solid-state impurities, and transparent magnetic materials.

  17. Echo Meadows Project Winter Artificial Recharge.

    Energy Technology Data Exchange (ETDEWEB)

    Ziari, Fred

    2002-12-19

    This report discusses the findings of the Echo Meadows Project (BPA Project 2001-015-00). The main purpose of this project is to artificially recharge an alluvial aquifer, WITH water from Umatilla River during the winter high flow period. In turn, this recharged aquifer will discharge an increased flow of cool groundwater back to the river, thereby improving Umatilla River water quality and temperature. A considerable side benefit is that the Umatilla River should improve as a habitat for migration, spanning, and rearing of anadromous and resident fish. The scope of this project is to provide critical baseline information about the Echo Meadows and the associated reach of the Umatilla River. Key elements of information that has been gathered include: (1) Annual and seasonal groundwater levels in the aquifer with an emphasis on the irrigation season, (2) Groundwater hydraulic properties, particularly hydraulic conductivity and specific yield, and (3) Groundwater and Umatilla River water quality including temperature, nutrients and other indicator parameters. One of the major purposes of this data gathering was to develop input to a groundwater model of the area. The purpose of the model is to estimate our ability to recharge this aquifer using water that is only available outside of the irrigation season (December through the end of February) and to estimate the timing of groundwater return flow back to the river. We have found through the data collection and modeling efforts that this reach of the river had historically returned as much as 45 cubic feet per second (cfs) of water to the Umatilla River during the summer and early fall. However, this return flow was reduced to as low as 10 cfs primarily due to reduced quantities of irrigation application, gain in irrigation efficiencies and increased groundwater pumping. Our modeling indicated that it is possible to restore these critical return flows using applied water outside of the irrigation season. We further

  18. Evaluation of the spoilage potential of bacteria isolated from spoiled raw salmon (Salmo salar) fillets stored under modified atmosphere packaging.

    Science.gov (United States)

    Macé, Sabrina; Joffraud, Jean-Jacques; Cardinal, Mireille; Malcheva, Mariya; Cornet, Josiane; Lalanne, Valérie; Chevalier, Frédérique; Sérot, Thierry; Pilet, Marie-France; Dousset, Xavier

    2013-01-01

    The spoilage potential of eight bacterial groups/species (Serratia spp., Hafnia alvei, Brochothrix thermosphacta, Carnobacterium maltaromaticum, Shewanella baltica, Lactococcus piscium, Photobacterium phosphoreum, "other Enterobacteriaceae" [containing one strain of Moellerella sp., Morganella sp. and Pectobacterium sp.]) isolated from spoiled raw salmon fillets stored under modified atmosphere packaging (MAP) was evaluated by inoculation into sterile raw salmon cubes followed by storage for 12days at 8°C. Microbial growth and sensory changes were monitored during the storage period. The dominant spoilage bacteria were C. maltaromaticum, H. alvei and P. phosphoreum. In order to further characterize their spoilage potential and to study the effect of their interactions, each of these 3 specific spoilage organisms (SSO) and two mixed-cultures, C. maltaromaticum/H. alvei and C. maltaromaticum/P. phosphoreum were tested in the sterile salmon model system using a combination of complementary methods: molecular (PCR-TTGE), sensory, chemical and conventional microbiological analyses. It was concluded that, in the mixed-culture inoculated samples, the dominant species determined the spoilage characteristics. The volatile fraction of P. phosphoreum inoculated samples was analyzed by solid-phase microextraction (SPME) followed by gas chromatography coupled to mass spectrometry (GC-MS). Among the specific volatile compounds present on P. phosphoreum spoiled inoculated samples, acetic acid was correlated with sensory analysis and can be proposed as a raw salmon spoilage marker. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Radiation-induced enhancement of antifungal activity of chitosan on fruit-spoiling fungi during postharvest storage

    International Nuclear Information System (INIS)

    Diep, Tran Bang; Lam, Nguyen Duy; Quynh, Tran Minh; Kume, Tamikazu

    2001-01-01

    Experiment conducted four fruit-spoiling fungal strains that were isolated from spoilt fruits (mango and dragon fruit) and were identified as follows: Fusarium dimerum Penzig, Aspergillus nidulans Wint, Aspergillus fumigatus Fresenius and Aspergillus japonicus Saito. Chitosan samples with various deacetylation degree (70-99%) were irradiated at doses ranging from 20 to 200kGy, then were supplemented to liquid medium for growth of fungi. We have found that chitosan possesses not only well known antibacterial activity but also the antifungal one on fruit-spoiling fungi. Method of fungal cultivation using liquid medium showed that it has higher sensitivity compared with the cultivation on agar plate, so we recommend this method should be used for evaluation of antimicrobial activity of chitosan. Our study also indicated that deacetylation degree of chitosan clearly affects its antifungal activity, the higher the deacetylation of chitosan, stronger antifungal activity can be observed. This finding recommends the use of chitosan with higher deacetylation for fruit coating and other pharmacology utilization. Results from the minimal inhibitory concentrations (MIC) on fungal growth showed that radiation treatment increased antifungal activity of chitosan and dose of 60kGy gave highest activity. (author)

  20. Radiation-induced enhancement of antifungal activity of chitosan on fruit-spoiling fungi during postharvest storage

    Energy Technology Data Exchange (ETDEWEB)

    Diep, Tran Bang; Lam, Nguyen Duy; Quynh, Tran Minh [Institute for Nuclear Science and Technique-VAEC, Hanoi (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Experiment conducted four fruit-spoiling fungal strains that were isolated from spoilt fruits (mango and dragon fruit) and were identified as follows: Fusarium dimerum Penzig, Aspergillus nidulans Wint, Aspergillus fumigatus Fresenius and Aspergillus japonicus Saito. Chitosan samples with various deacetylation degree (70-99%) were irradiated at doses ranging from 20 to 200kGy, then were supplemented to liquid medium for growth of fungi. We have found that chitosan possesses not only well known antibacterial activity but also the antifungal one on fruit-spoiling fungi. Method of fungal cultivation using liquid medium showed that it has higher sensitivity compared with the cultivation on agar plate, so we recommend this method should be used for evaluation of antimicrobial activity of chitosan. Our study also indicated that deacetylation degree of chitosan clearly affects its antifungal activity, the higher the deacetylation of chitosan, stronger antifungal activity can be observed. This finding recommends the use of chitosan with higher deacetylation for fruit coating and other pharmacology utilization. Results from the minimal inhibitory concentrations (MIC) on fungal growth showed that radiation treatment increased antifungal activity of chitosan and dose of 60kGy gave highest activity. (author)

  1. Quantitative determination of sediment movement at the landward spoil ground in the Yangtze Estuary with radioactive tracer

    International Nuclear Information System (INIS)

    Li Zhangsu

    1993-01-01

    A radioactive tracer experiment was carried out at the landward spoil ground of the North Passage in the Yangtze Estuary in June of 1991. The scandium-46 was selected as the tracer, the total activity released is 17.95 x 10 10 Bq(4.85 Ci), the amount of the scandium-46 glass is 495 g. The purpose of the experiment is to determine the sediment movement direction, path, velocity and transport rate. The experiment provides the direct evidence for using the landward spoil ground in the future. The experiment results show the sediment movement was governed by the ebb tide current during the period of middle and neap tides when the radioactive tracer was injected both on the flood and ebb tides, and the sediment moved from the injection points to the middle of the North Passage near the navigation buoy No. 269. The direction of the sediment movement is 110 degree, the particle velocity is 758 m/d, and the sediment transport rate per unit width is 47.8 m 3 /md

  2. Environmental risk evaluation of the use of mine spoils and treated sewage sludge in the ecological restoration of limestone quarries

    Science.gov (United States)

    Jordán, M. M.; Pina, S.; García-Orenes, F.; Almendro-Candel, M. B.; García-Sánchez, E.

    2008-07-01

    The ecologic restoration criteria in areas degraded from extraction activities require making use of their mine spoils. These materials do not meet fertility conditions to guarantee restoration success and therefore, need the incorporation of organic amendments to obtain efficient substratum. Reducing the deficiencies in the organic material and restoration material nutrients with the contribution of treated sewage sludge is proposed in this work. This experiment was based on a controlled study using columns. The work was conducted with two mine spoils, both very rich in calcium carbonate. The first mineral, of poor quality, came from the formation of aggregates of crushed limestone ( Z). The other residual material examined originated in limestone extraction, formed by the levels of interspersed non-limestone materials and the remains of stripped soils ( D). Two treatments were undertaken (30,000 and 90,000 kg/ha of sewage sludge), in addition to a control treatment. The water contribution was carried out with a device that simulated either short-duration rain or a flooding irrigation system in order to cover the surface and then percolate through the soil. The collection of leached water took place 24 h after the applications. Different parameters of the leached water were determined, including pH, electrical conductivity, nitrate anions, ammonium, phosphates, sulphates and chlorides. The values obtained for each irrigation application are discussed, and the nitrate values obtained were very elevated.

  3. Detection of generalized synchronization using echo state networks

    Science.gov (United States)

    Ibáñez-Soria, D.; Garcia-Ojalvo, J.; Soria-Frisch, A.; Ruffini, G.

    2018-03-01

    Generalized synchronization between coupled dynamical systems is a phenomenon of relevance in applications that range from secure communications to physiological modelling. Here, we test the capabilities of reservoir computing and, in particular, echo state networks for the detection of generalized synchronization. A nonlinear dynamical system consisting of two coupled Rössler chaotic attractors is used to generate temporal series consisting of time-locked generalized synchronized sequences interleaved with unsynchronized ones. Correctly tuned, echo state networks are able to efficiently discriminate between unsynchronized and synchronized sequences even in the presence of relatively high levels of noise. Compared to other state-of-the-art techniques of synchronization detection, the online capabilities of the proposed Echo State Network based methodology make it a promising choice for real-time applications aiming to monitor dynamical synchronization changes in continuous signals.

  4. Acoustic Echo Cancellation Using Sub-Adaptive Filter

    Science.gov (United States)

    Ohta, Satoshi; Kajikawa, Yoshinobu; Nomura, Yasuo

    In the acoustic echo canceller (AEC), the step-size parameter of the adaptive filter must be varied according to the situation if double talk occurs and/or the echo path changes. We propose an AEC that uses a sub-adaptive filter. The proposed AEC can control the step-size parameter according to the situation. Moreover, it offers superior convergence compared to the conventional AEC even when the double talk and the echo path change occur simultaneously. Simulations demonstrate that the proposed AEC can achieve higher ERLE and faster convergence than the conventional AEC. The computational complexity of the proposed AEC can be reduced by reducing the number of taps of the sub-adaptive filter.

  5. A spin echo study of A15 intermetallic compounds

    International Nuclear Information System (INIS)

    Schoep, G.K.

    1976-01-01

    This thesis mainly concerns the measurement of spin-lattice relaxation times in intermetallic compounds of the bcc lattice structure, having the formula V 3 X (C = Pt, Ir, Os, Pd, Rh, Ni, Co, Au). When, in a spin echo experiment, a two-pulse sequence was applied, several quadrupolar echoes were observed. Special attention is given to the 'forbidden' echoes (absol.(Δm')GT1) in V 3 Au and V 3 Co. In relation to the V 3 X compounds, several characteristics are discussed including temperature dependence and concentration dependence of spin relaxation times, superconductivity and the importance of d-state electrons in determination of the spin relaxation times. Finally, the above characteristics were determined for 6 different samples of the vanadium-gold alloy, V 3 Au, specifically

  6. Design And Simulation Of An Acoustic Echo Cancellation System For Hand-Free Telecommunication

    Directory of Open Access Journals (Sweden)

    Ein Gyin Pwint

    2015-06-01

    Full Text Available Abstract Acoustic echo cancellation is a common occurrence in todays telecommunication systems. The signal interference caused by acoustic echo is distracting to users and causes a reduction in the quality of the communication. This paper is implementing the overall system of acoustic echo cancellation system using LMS and NLMS algorithms for adaptive filter normalized cross correlation NCC algorithm double talk detector. The result of echo return loss enhancement ERLE and mean squared error MSE which show that how much the amount of echo signal cancelled and the amount of residual error signal for cancelling acoustic echo cancellation on a PC with the help of the MATLAB software.

  7. Echo intensity of the rectus femoris in stable COPD patients

    Directory of Open Access Journals (Sweden)

    Ye X

    2017-10-01

    Full Text Available Xiong Ye,1 Mingjie Wang,2 Hui Xiao2 1College of Clinical Medicine, Shanghai University of Medicine & Health Sciences, 2Department of Respiratory Medicine, Shanghai General Hospital, Shanghai Jiaotong University, Shanghai, China Objective: The aim of this study was to investigate whether echo intensity of the rectus femoris when measured using ultrasound can distinguish muscles affected by COPD compared with healthy non-COPD affected muscles and whether the severity of ultrasonic abnormalities was associated with health-related quality of life (HRQoL. Methods: Echo intensity, areas of the rectus femoris, and the thickness of quadriceps muscles were measured using ultrasound in 50 COPD outpatients and 21 age-matched non-COPD controls. The results of the 8-Item Short-Form Health Survey and the functional assessment of chronic illness therapy fatigue scales were used to evaluate HRQoL. Results: There was a significantly higher echo intensity of the rectus femoris in all stages of COPD patients than in age-matched non-COPD subjects; the quadriceps muscle thickness and cross-sectional area of the rectus femoris significantly decreased in COPD GOLD III–IV only. Furthermore, in our stable COPD patients, echo intensity of the rectus femoris was associated with HRQoL independently. Conclusion: Quantitative ultrasound distinguishes healthy muscles from those affected by COPD grade I–IV, and quality and quantity of muscles are associated with HRQoL and forced expiratory volume in 1 second. Ultrasonic echo intensity of the rectus femoris may be a useful instrument for assessing disease severity and monitoring the changes of skeletal muscle resulting from disease progression or clinical intervention in patients with COPD. Keywords: echo intensity, ultrasound, rectus femoris, chronic obstructive pulmonary disease

  8. A computational model for biosonar echoes from foliage.

    Directory of Open Access Journals (Sweden)

    Chen Ming

    Full Text Available Since many bat species thrive in densely vegetated habitats, echoes from foliage are likely to be of prime importance to the animals' sensory ecology, be it as clutter that masks prey echoes or as sources of information about the environment. To better understand the characteristics of foliage echoes, a new model for the process that generates these signals has been developed. This model takes leaf size and orientation into account by representing the leaves as circular disks of varying diameter. The two added leaf parameters are of potential importance to the sensory ecology of bats, e.g., with respect to landmark recognition and flight guidance along vegetation contours. The full model is specified by a total of three parameters: leaf density, average leaf size, and average leaf orientation. It assumes that all leaf parameters are independently and identically distributed. Leaf positions were drawn from a uniform probability density function, sizes and orientations each from a Gaussian probability function. The model was found to reproduce the first-order amplitude statistics of measured example echoes and showed time-variant echo properties that depended on foliage parameters. Parameter estimation experiments using lasso regression have demonstrated that a single foliage parameter can be estimated with high accuracy if the other two parameters are known a priori. If only one parameter is known a priori, the other two can still be estimated, but with a reduced accuracy. Lasso regression did not support simultaneous estimation of all three parameters. Nevertheless, these results demonstrate that foliage echoes contain accessible information on foliage type and orientation that could play a role in supporting sensory tasks such as landmark identification and contour following in echolocating bats.

  9. MPD model for radar echo signal of hypersonic targets

    Directory of Open Access Journals (Sweden)

    Xu Xuefei

    2014-08-01

    Full Text Available The stop-and-go (SAG model is typically used for echo signal received by the radar using linear frequency modulation pulse compression. In this study, the authors demonstrate that this model is not applicable to hypersonic targets. Instead of SAG model, they present a more realistic echo signal model (moving-in-pulse duration (MPD for hypersonic targets. Following that, they evaluate the performances of pulse compression under the SAG and MPD models by theoretical analysis and simulations. They found that the pulse compression gain has an increase of 3 dB by using the MPD model compared with the SAG model in typical cases.

  10. Beam divergence correction method for neutron resonance spin echo spectroscope

    International Nuclear Information System (INIS)

    Maruyama, Ryuji; Tasaki, Seiji; Hino, Masahiro; Kitaguchi, Masaaki; Kawabata, Yuji; Ebisawa, Toru

    2005-01-01

    A beam divergence correction method for Neutron resonance spin echo (NRSE) spectroscope was proposed and the effectiveness is evaluated by simulation. When a beam divergence correction coil was introduced into NRSE spectroscope and the optimum magnetic field was given, the visibility of spin echo signal was recovered by controlling scattering of phase difference generated by beam divergence. The effectiveness of the correction method was proved by the above result. Principle of NRSE spectroscopy, decrease of spin polarization rate by beam divergence and its correction method, structure of divergence angle correction coil and the magnetic field calculation and result of simulation are described. (S.Y.)

  11. A short TE gradient-echo sequence using asymmetric sampling

    International Nuclear Information System (INIS)

    Fujita, Norihiko; Harada, Kohshi; Sakurai, Kosuke; Nakanishi, Katsuyuki; Kim, Shyogen; Kozuka, Takahiro

    1990-01-01

    We have developed a gradient-echo pulse sequence with a short TE less than 4 msec using a data set of asymmetric off-center sampling with a broad bandwidth. The use of such a short TE significantly reduces T 2 * dephasing effect even in a two-dimensional mode, and by collecting an off-center echo, motion-induced phase dispersion is also considerably decreased. High immunity of this sequence to these dephasing effects permits clear visualization of anatomical details near the skull base where large local field inhomogeneities and rapid blood flow such as in the internal carotid artery are present. (author)

  12. High angular resolution diffusion imaging with stimulated echoes

    DEFF Research Database (Denmark)

    Lundell, Henrik; Alexander, Daniel C; Dyrby, Tim B

    2014-01-01

    Stimulated echo acquisition mode (STEAM) diffusion MRI can be advantageous over pulsed-gradient spin-echo (PGSE) for diffusion times that are long compared with T2 . It therefore has potential for biomedical diffusion imaging applications at 7T and above where T2 is short. However, gradient pulses...... angular resolution diffusion imaging (HARDI) data were acquired with and without the proposed compensation. The data were processed to derive standard diffusion tensor imaging (DTI) maps, which highlight the need for the compensation. Ignoring the other gradient pulses, a bias in DTI parameters from STEAM...

  13. Fish target strength estimation using multiple echo statistics

    Science.gov (United States)

    Moszynski, M.

    2002-03-01

    When fish strength is estimated indirectly from the sounder echo amplitudes, the inverse techniques of solving the so-called “single-beam integral equation” are quite satisfactorily used. This approach needs prior knowledge of the beam pattern PDF, as it represents the kernel of the integral equation to be solved and is usually calculated under the assumption of a uniform spatial distribution of fish. However, it may be shown that in some cases this assumption is not necessarily justified. For instance, when the density of fish increases, one receives multiple echoes from the same single fish in successive transmissions, which results in observing so-called fish echo traces. Typically used fish counting methods are either simple direct echo counting statistics or fish traces statistics [1]. Increased fish concentration is not only the reason of multiple echo formation resulting in the fish traces in consecutive pings. As it is easily seen from the geometry of the phenomenon, even a relatively low-density fish aggregation forms multiple echoes and, hence, fish traces if the vessel (or fish) relative speed is low enough and the beam pattern angular width (sampling volume) is large enough. In some situations, the uniform assumption works properly only for the cases of large numbers of samples. Taking into account this phenomenon, the accuracy of the solution can be improved by including the fish traces counting statistics in calculating the beam pattern PDF. In this paper, two different models of fish traces statistics are investigated: one assuming the vessel movement with stationary fish and the other with a stationary vessel and moving fish. Both approaches are modeled numerically and verified experimentally using the data obtained from a dual-beam system. The comparison of both approaches, i.e., for single echo traces and multiple echoes, is carried out using Windowed Singular Value Decomposition (WSVD) and Expectation Maximization and Smoothing (EMS) inverse

  14. Experiments on the survival of six brackish macro-invertebrates from the Baltic Sea after dredged spoil coverage and its implications for the field

    Science.gov (United States)

    Powilleit, M.; Graf, G.; Kleine, J.; Riethmüller, R.; Stockmann, K.; Wetzel, M. A.; Koop, J. H. E.

    2009-02-01

    the organisms ( N. hombergii and M. arenaria) to reach the sediment surface after burial. This was not observed for the other test species. While crawling upward to the new sediment surfaces burrowing velocities of up to 8 cm d - 1 were observed for the bivalves and up to 20 cm d - 1 for N. hombergii. Between 17 and 79% of the test organisms showed burrowing activity after experimental burial. The survival rate (defined as the ability to regained contact with the sediment surface) ranged from 0 to 33%, depending on species and on burial depth. The organisms reached the sediment surface by burrowing (polychaetes and bivalves) and/or by extending their siphons to the new sediment surface (bivalves). The extrapolation of laboratory survival rates to the two disposal sites was obtained based on the in situ thicknesses of the dredged spoil layers measured by multi-beam echo sounder. This resulted in total average survival rate estimates for the test species of 45 and 43% for the two disposal sites. The results obtained during the laboratory tests and the following extrapolation to the field were verified by the range of results from a previous field study, using grab sampling shortly before and after a disposal event in June 2001. The effect of dredged material disposal on the tested Baltic Sea benthic macrofauna was assessed by extrapolating the verified laboratory results to the field.

  15. Accuracy of magnetic resonance imaging for measuring maturing cartilage: A phantom study.

    Science.gov (United States)

    McKinney, Jennifer R; Sussman, Marshall S; Moineddin, Rahim; Amirabadi, Afsaneh; Rayner, Tammy; Doria, Andrea S

    2016-07-01

    To evaluate the accuracy of magnetic resonance imaging measurements of cartilage tissue-mimicking phantoms and to determine a combination of magnetic resonance imaging parameters to optimize accuracy while minimizing scan time. Edge dimensions from 4 rectangular agar phantoms ranging from 10.5 to 14.5 mm in length and 1.25 to 5.5 mm in width were independently measured by two readers using a steel ruler. Coronal T1 spin echo (T1 SE), fast spoiled gradient-recalled echo (FSPGR) and multiplanar gradient-recalled echo (GRE MPGR) sequences were used to obtain phantom images on a 1.5-T scanner. Inter- and intra-reader reliability were high for both direct measurements and for magnetic resonance imaging measurements of phantoms. Statistically significant differences were noted between the mean direct measurements and the mean magnetic resonance imaging measurements for phantom 1 when using a GRE MPGR sequence (512x512 pixels, 1.5-mm slice thickness, 5:49 min scan time), while borderline differences were noted for T1 SE sequences with the following parameters: 320x320 pixels, 1.5-mm slice thickness, 6:11 min scan time; 320x320 pixels, 4-mm slice thickness, 6:11 min scan time; and 512x512 pixels, 1.5-mm slice thickness, 9:48 min scan time. Borderline differences were also noted when using a FSPGR sequence with 512x512 pixels, a 1.5-mm slice thickness and a 3:36 min scan time. FSPGR sequences, regardless of the magnetic resonance imaging parameter combination used, provided accurate measurements. The GRE MPGR sequence using 512x512 pixels, a 1.5-mm slice thickness and a 5:49 min scan time and, to a lesser degree, all tested T1 SE sequences produced suboptimal accuracy when measuring the widest phantom.

  16. MR diagnosis of temporomandibular arthrosis

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Shigeaki [Kagoshima Univ. (Japan). Faculty of Dentistry

    1996-09-01

    This review described lesions of articular disk and its surrounding tissues revealed by MR examination in temporomandibular arthrosis, and problems and limits of the examination. Apparatus and imaging methods: Spin echo method was generally used and gradient echo method was alternatively used. Author`s apparatus was 1.5 tesla Signa, Advantage type, equipped with surface coil for temporomandibular joint. Imaging conditions were T1-weighted spin echo method, T2-weighted fast spin echo method, spoiled GRASS (gradient recalled acquisition in the steady state) method and GRASS method. MR findings of articular disk: MR images of normal and abnormal temporomandibular joint were presented together with computed radiographic findings. The role of dynamic imaging was described for evaluation and analysis of the joint functioning. MR findings of surrounding tissues of the disk: Dynamic MRI of the tissues was found useful to see whether the cause of pain was present inside or outside of the articular capsule. Joint effusion could not be fully imaged in T2-weighted conditions. (K.H.)

  17. MR diagnosis of temporomandibular arthrosis

    International Nuclear Information System (INIS)

    Suenaga, Shigeaki

    1996-01-01

    This review described lesions of articular disk and its surrounding tissues revealed by MR examination in temporomandibular arthrosis, and problems and limits of the examination. Apparatus and imaging methods: Spin echo method was generally used and gradient echo method was alternatively used. Author's apparatus was 1.5 tesla Signa, Advantage type, equipped with surface coil for temporomandibular joint. Imaging conditions were T1-weighted spin echo method, T2-weighted fast spin echo method, spoiled GRASS (gradient recalled acquisition in the steady state) method and GRASS method. MR findings of articular disk: MR images of normal and abnormal temporomandibular joint were presented together with computed radiographic findings. The role of dynamic imaging was described for evaluation and analysis of the joint functioning. MR findings of surrounding tissues of the disk: Dynamic MRI of the tissues was found useful to see whether the cause of pain was present inside or outside of the articular capsule. Joint effusion could not be fully imaged in T2-weighted conditions. (K.H.)

  18. Ameliorating effects of industrial sugar residue on the Jales gold mine spoil (NE Portugal) using Holcus lanatus and Phaseolus vulgaris as indicators

    International Nuclear Information System (INIS)

    Bleeker, P.M.; Teiga, P.M.; Santos, M.H.; Koe, T. de; Verkleij, J.A.C.

    2003-01-01

    A residue of the sugar industry can be used in revegetation programs on metal contaminated sites. - Phytostabilisation of bare heavily contaminated substrate, such as abandoned mine sites, is considered a very appropriate technology in order to diminish erosion and dispersion of contaminants into the surroundings. In this short-term pot study, application of industrial sugar residue (ISR), a waste product of the sugar industry, proved to ameliorate spoils conditions for plant performance by elevating pH and immobilising several metals. Although arsenate concentrations were positively correlated to spoil pH and spoil treatment with ISR mobilised As, growth of both Phaseolus vulgaris and Holcus lanatus improved significantly after applications of 3.75 g ISR kg -1 dry spoil. Nutrient uptake from the substrate, with the exception of potassium, was elevated by ISR. As a remediation technique ISR application could be effective although in As-contaminated sites application might be restricted to areas where leaching to (ground) water does not form a risk

  19. Harmonic Components Based Post-Filter Design for Residual Echo Suppression

    Science.gov (United States)

    Lee, Minwoo; Lee, Yoonjae; Kim, Kihyeon; Ko, Hanseok

    In this Letter, a residual acoustic echo suppression method is proposed to enhance the speech quality of hands-free communication in an automobile environment. The echo signal is normally a human voice with harmonic characteristics in a hands-free communication environment. The proposed algorithm estimates the residual echo signal by emphasizing its harmonic components. The estimated residual echo is used to obtain the signal-to-interference ratio (SIR) information at the acoustic echo canceller output. Then, the SIR based Wiener post-filter is constructed to reduce both the residual echo and noise. The experimental results confirm that the proposed algorithm is superior to the conventional residual echo suppression algorithm in terms of the echo return loss enhancement (ERLE) and the segmental signal-to-noise ratio (SEGSNR).

  20. Correction of echo shift in reconstruction processing for ultra-short TE pulse sequence

    International Nuclear Information System (INIS)

    Takizawa, Masahiro; Ootsuka, Takehiro; Abe, Takayuki; Takahashi, Tetsuhiko

    2010-01-01

    An ultra-short echo time (TE) pulse sequence is composed of a radial sampling that acquires echo signals radially in the K-space and a half-echo acquisition that acquires only half of the echo signal. The shift in the position of the echo signal (echo shift) caused by the timing errors in the gradient magnetic field pulses affects the image quality in the radial sampling with the half-echo acquisition. To improve image quality, we have developed a signal correction algorithm that detects and eliminates this echo shift during reconstruction by performing a pre-scan within 10 seconds. The results showed that image quality is improved under oblique and/or off-centering conditions that frequently cause image distortion due to hardware error. In conclusion, we have developed a robust ultra-short TE pulse sequence that allows wide latitude in the scan parameters, including oblique and off-centering conditions. (author)

  1. Seafloor characterisation using echo peak amplitudes of multibeam hydrosweep system - A preliminary study at Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Sudhakar, T.

    In this paper an interface to acquire 59-beams echo peak amplitudes of the Hydrosweep Multibeam system is established. The echo peak amplitude values collected at varying seabed provinces of Arabian sea are presented. The study reveals...

  2. Pre-IceBridge MCoRDS L1B Geolocated Radar Echo Strength Profiles

    Data.gov (United States)

    National Aeronautics and Space Administration — The Pre-IceBridge MCoRDS L1B Geolocated Radar Echo Strength Profiles (BRMCR1B) data set contains Arctic and Antarctic radio echo-sounding measurements taken from the...

  3. Edward Albee’s The Zoo Story: Echo/es of Contemporary Subversive Culture

    Directory of Open Access Journals (Sweden)

    Naqibun Nabi

    2016-02-01

    Full Text Available The post-world war II American social and cultural setting was ambiguously featured with enforced conformity in the name of prosperity and Americanization of the nation. Despite of this fact, American writers, especially, dramatists conveyed their message against this fixation through variety and intellectuality. Edward Albee’s The Zoo Story is one of those literary assets which dedicatedly cut through the illusions of contemporary American social and cultural ethos. Here, his characters are seen struggling constantly with their insecurities and existential angst in the society. He presents America, the so-called ‘Land of Free and Home of Braves’ (note 1, in such a portrayal that unveils the traps of cages and confinement underneath. The target of this paper is to trace Edward Albee’s heightened awareness about the post-war American socio-cultural reality evident in The Zoo Story. It also looks for the voice in which the text echoes out the anti-communist, materialistic, gender-coded boundaries, coupled with paradoxical media representations, religious bordering and how Albee challenges these issues with an anti-establishment tone. Keywords: subversive culture, anti-communism, media, religion and homosexuality

  4. Diverse Evill Persons: Echoes in the Landscape, Echoes in the Archives

    Directory of Open Access Journals (Sweden)

    Martin Bashforth

    2011-12-01

    Full Text Available This is an account of a process, the working together of cross-disciplinary insights between an artist and a historian, to create a means by which members of the public might encounter the past on their own terms. In the summer of 2009, the historian [MB] and the conceptual artist [PB] decided to collaborate on a project based around events at Cannon Hall, Cawthorne in the West Riding of Yorkshire, 1673-74. The events are located in the B family genealogy but carry in them echoes of deeper social and economic forces in the past, as well as relevance to modern debates about crime, welfare and justice. The aim of the project is to create an exhibition/installation within which members of the public can experience what it means to make sense of the past through the prism of the present. The project is intended to challenge normative approaches in museology and the interpretation of heritage objects, places and documents. The article explores the foundational processes and concepts.

  5. Compton echoes from nearby Gamma-Ray Bursts

    Science.gov (United States)

    Beniamini, Paz; Giannios, Dimitrios; Younes, George; van der Horst, Alexander J.; Kouveliotou, Chryssa

    2018-03-01

    The recent discovery of gravitational waves from GW170817, associated with a short Gamma-Ray Burst (GRB) at a distance of 40Mpc, has demonstrated that short GRBs can occur locally and at a reasonable rate. Furthermore, gravitational waves enable us to detect close by GRBs, even when we are observing at latitudes far from the jet's axis. We consider here Compton echoes, the scattered light from the prompt and afterglow emission. Compton echoes, an as yet undetected counterpart of GRBs, peak in X-rays and maintain a roughly constant flux for hundreds to thousands of years after the burst. Though too faint to be detected in typical cosmological GRBs, a fraction of close by bursts with a sufficiently large energy output in X-rays, and for which the surrounding medium is sufficiently dense, may indeed be observed in this way. The detection of a Compton echo could provide unique insight into the burst properties and the environment's density structure. In particular, it could potentially determine whether or not there was a successful jet that broke through the compact binary merger ejecta. We discuss here the properties and expectations from Compton echoes and suggest methods for detectability.

  6. Inserting digital watermark by method on delaying echo

    Directory of Open Access Journals (Sweden)

    Vitaliy Grigorievich Ivanenko

    2016-03-01

    Full Text Available The questions of the fight against piracy in media, using digital watermarks have considered. Main requirements have been formulated, which integration method have to satisfy. Method of inserting digital watermark, founded on delay echo. Principal characteristics of applications of chosen method have been listed.

  7. Communication: Phase incremented echo train acquisition in NMR spectroscopy.

    Science.gov (United States)

    Baltisberger, Jay H; Walder, Brennan J; Keeler, Eric G; Kaseman, Derrick C; Sanders, Kevin J; Grandinetti, Philip J

    2012-06-07

    We present an improved and general approach for implementing echo train acquisition (ETA) in magnetic resonance spectroscopy, particularly where the conventional approach of Carr-Purcell-Meiboom-Gill (CPMG) acquisition would produce numerous artifacts. Generally, adding ETA to any N-dimensional experiment creates an N + 1 dimensional experiment, with an additional dimension associated with the echo count, n, or an evolution time that is an integer multiple of the spacing between echo maxima. Here we present a modified approach, called phase incremented echo train acquisition (PIETA), where the phase of the mixing pulse and every other refocusing pulse, φ(P), is incremented as a single variable, creating an additional phase dimension in what becomes an N + 2 dimensional experiment. A Fourier transform with respect to the PIETA phase, φ(P), converts the φ(P) dimension into a Δp dimension where desired signals can be easily separated from undesired coherence transfer pathway signals, thereby avoiding cumbersome or intractable phase cycling schemes where the receiver phase must follow a master equation. This simple modification eliminates numerous artifacts present in NMR experiments employing CPMG acquisition and allows "single-scan" measurements of transverse relaxation and J-couplings. Additionally, unlike CPMG, we show how PIETA can be appended to experiments with phase modulated signals after the mixing pulse.

  8. Infrared photon-echo spectroscopy of water : The thermalization effects

    NARCIS (Netherlands)

    Pshenichnikov, Maxim S.; Yeremenko, Sergey; Wiersma, Douwe A.; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De

    2005-01-01

    The larger part of the nonlinear response in IR photon-echo and transient-grating spectroscopy on HDO-D2O mixtures at > 1-ps delays is found to originate from the D2O refractive index modulation due to local volume thermalization.

  9. Relativistic electron dropout echoes induced by interplanetary shocks

    Science.gov (United States)

    Schiller, Q.; Kanekal, S. G.; Boyd, A. J.; Baker, D. N.; Blake, J. B.; Spence, H. E.

    2017-12-01

    Interplanetary shocks that impact Earth's magnetosphere can produce immediate and dramatic responses in the trapped relativistic electron population. One well-studied response is a prompt injection capable of transporting relativistic electrons deep into the magnetosphere and accelerating them to multi-MeV energies. The converse effect, electron dropout echoes, are observations of a sudden dropout of electron fluxes observed after the interplanetary shock arrival. Like the injection echo signatures, dropout echoes can also show clear energy dispersion signals. They are of particular interest because they have only recently been observed and their causal mechanism is not well understood. In the analysis presented here, we show observations of electron drift echo signatures from the Relativistic Electron-Proton Telescope (REPT) and Magnetic Electron and Ion Sensors (MagEIS) onboard NASA's Van Allen Probes mission, which show simultaneous prompt enhancements and dropouts within minutes of the associated with shock impact. We show that the observations associated with both enhancements and dropouts are explained by the inward motion caused by the electric field impulse induced by the interplanetary shock, and either energization to cause the enhancement, or lack of a seed population to cause the dropout.

  10. A simple prescan calibration procedure for Ultrashort echo time imaging

    Czech Academy of Sciences Publication Activity Database

    Latta, P.; Starčuk jr., Zenon; Gruwel, M.; Tománek, B.

    2016-01-01

    Roč. 29, S1 (2016), S42 E-ISSN 1352-8661. [ESMRMB 2016 Congress. 29.09.2016-01.10.2016, Vienna] R&D Projects: GA ČR(CZ) GA15-12607S Institutional support: RVO:68081731 Keywords : ultrashort echo time * calibration * prescan procedure Subject RIV: FS - Medical Facilities ; Equipment

  11. Echos, Doubles, and Delusions : Capgras Syndrome in Science and Literature

    NARCIS (Netherlands)

    Draaisma, Douwe

    2009-01-01

    Mark Schluter, the main protagonist in Richard Powers's The Echo Maker (2006), suffers from Capgras Syndrome, a disorder characterized by the patient's delusional belief that his near ones are replaced by doubles. Since its initial identification in 1923, Capgras Syndrome has had a two-stage

  12. Echo Behavior in Large Populations of Chemical Oscillators

    Directory of Open Access Journals (Sweden)

    Tianran Chen

    2016-12-01

    Full Text Available Experimental and theoretical studies are reported, for the first time, on the observation and characterization of echo phenomena in oscillatory chemical reactions. Populations of uncoupled and coupled oscillators are globally perturbed. The macroscopic response to this perturbation dies out with time: At some time τ after the perturbation (where τ is long enough that the response has died out, the system is again perturbed, and the initial response to this second perturbation again dies out. Echoes can potentially appear as responses that arise at 2τ,3τ,... after the first perturbation. The phase-resetting character of the chemical oscillators allows a detailed analysis, offering insights into the origin of the echo in terms of an intricate structure of phase relationships. Groups of oscillators experiencing different perturbations are analyzed with a geometric approach and in an analytical theory. The characterization of echo phenomena in populations of chemical oscillators reinforces recent theoretical studies of the behavior in populations of phase oscillators [E. Ott et al., Chaos 18, 037115 (2008]. This indicates the generality of the behavior, including its likely occurrence in biological systems.

  13. Characterization of trehalose aqueous solutions by neutron spin echo

    CERN Document Server

    Branca, C; Magazù, S; Maisano, G; Mangione, A; Pappas, C; Triolo, A

    2002-01-01

    The present work reports neutron spin-echo (NSE) results on aqueous mixtures of trehalose, a naturally occurring disaccharide of glucose, which shows an extraordinary bioprotective effectiveness against dehydration and freezing. The aim of the work is to furnish new results on the dynamics of the trehalose/water system on the nano- and picosecond scales. (orig.)

  14. A novel method for pulse-echo ultrasonic tomograph

    International Nuclear Information System (INIS)

    Pereira, W.C.A.; Machado, J.C.

    1989-01-01

    A new method to obtain one-dimensional map of ultrasonic wave speed is proposed. The method consists of insonifying a medium with an ultrasonic pulse and receiving the reflected echo on the same transducer used as transmitter and in another one placed adjacent. Each interface iluminated by the irradiated wave returns an echo to both transducers. Then by measuring the time-of-flight for each echo arrived on both transducers, the position of each interface, related to the transmitting transducer, and the wave speed existent between consecutive interfaces can be obtained. In the present work a phantom was made. Consisting of 3 layers: epoxi(9,9mm), acrilic (9.7mm) and pvc (10.2mm). The phantom was imersed in a tank filled with water, together with a holder with the 2 transducer in it. Using a digital osciloscope and microcomputer can implement the method proposed. The values calculated for the distancers interface-transducers have shown errors from 0.1% to and can be acceptable to a certain extent. On the other hand, all the obtained for the width of layers and for the of the US wave inside them are acceptable. The width of the of the echo from interface acrilic-pvc and it is necesary an exciting pulse with greater amplitude to enhance it. Results can be accepted as first approximation and encourage us to proceed exploring this method. (author) [pt

  15. Echo width of foam supports used in scattering measurements

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen; Solodukhov, V. V.

    1979-01-01

    Theoretically and experimentally determined echo widths of dielectric cylinders having circular, triangular, and quadratic cross sections have been compared. The cylinders were made of foam material having a relative dielectric constant of about 1.035. The purpose of the investigation was to find...

  16. Skeletal muscle ultrasound: correlation between fibrous tissue and echo intensity.

    NARCIS (Netherlands)

    Pillen, S.; Tak, R.O.; Zwarts, M.J.; Lammens, M.M.Y.; Verrijp, K.; Arts, I.M.P.; Laak, J.A.W.M. van der; Hoogerbrugge, P.M.; Engelen, B.G.M. van; Verrips, A.

    2009-01-01

    In this study, we examined the correlation between muscle ultrasound and muscle structure. Echo intensity (EI) of 14 muscles of two golden retriever muscular dystrophy dogs was correlated to the percentage interstitial fibrous tissue and fat in muscle biopsy. A significant correlation between

  17. Analysis of multibeam-hydrosweep echo peaks for seabed characterisation

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Schenke, H.W.; Kodagali, V.N.; Hagen, R.

    , in general, Gaussian in nature except in the case of the Kainan Maru seamount summit (area D). The outer beams of the Enderby abyssal plain (area C) echo-peak PDF statistics reveal the highest possible large-scale feature dominance. Interestingly, Extremal...

  18. HF Radar Sea-echo from Shallow Water

    Directory of Open Access Journals (Sweden)

    Josh Kohut

    2008-08-01

    Full Text Available HF radar systems are widely and routinely used for the measurement of ocean surface currents and waves. Analysis methods presently in use are based on the assumption of infinite water depth, and may therefore be inadequate close to shore where the radar echo is strongest. In this paper, we treat the situation when the radar echo is returned from ocean waves that interact with the ocean floor. Simulations are described which demonstrate the effect of shallow water on radar sea-echo. These are used to investigate limits on the existing theory and to define water depths at which shallow-water effects become significant. The second-order spectral energy increases relative to the first-order as the water depth decreases, resulting in spectral saturation when the waveheight exceeds a limit defined by the radar transmit frequency. This effect is particularly marked for lower radar transmit frequencies. The saturation limit on waveheight is less for shallow water. Shallow water affects second-order spectra (which gives wave information far more than first-order (which gives information on current velocities, the latter being significantly affected only for the lowest radar transmit frequencies for extremely shallow water. We describe analysis of radar echo from shallow water measured by a Rutgers University HF radar system to give ocean wave spectral estimates. Radar-derived wave height, period and direction are compared with simultaneous shallow-water in-situ measurements.

  19. Development of spin echo small angle neutron scattering

    International Nuclear Information System (INIS)

    Bouwman, W.G.; Uca, O.; Van Oossanen, M.; Kraan, W.H.; Rekveldt, M.T.

    1999-01-01

    A novel kind of small angle neutron scattering (SANS) instrument is being built, based on the Larmor precession of polarised neutrons in a magnetic field. A spin echo of the polarised neutrons is used to detect the scattering. The basis of this instrument is a symmetric set-up with a spin flipper in the centre, which creates a spin echo, even with a divergent beam. The precession regions on either side of the spin flipper are shaped such to produce a very sensitive relation between the vertical angle of the neutron path and the total precession angle on one side. Any SANS of a sample placed in the instrument changes the symmetry of the neutron path and therefore decreases the echo. This amounts to measuring only the difference of the incoming and outgoing angle. This gives a huge increase in intensity of the signal with respect to conventional SANS in which both incoming and outgoing angle are defined. Magnetised foils, which rotate the neutron spin between being parallel to the magnetic field and perpendicular to the field are used to start or terminate the precession. With a preliminary set-up the first spin echo SANS signal have been measured. A full correlation function in samples over distances from 5 to 1000 nm is expected to be measured in some minutes. (author)

  20. Participatory Culture at the Echo Park Film Center

    Science.gov (United States)

    Rosales, Jennifer Ann

    2013-01-01

    The Echo Park Film Center, a Los Angeles nonprofit media education organization, teaches underprivileged youth how to comprehend and make media in order to empower them to speak and be heard. Due to the organization's nonmainstream media courses and its connection to its community, the Center is able to create a participatory and socially…

  1. Subband Affine Projection Algorithm for Acoustic Echo Cancellation System

    Directory of Open Access Journals (Sweden)

    Hyeon-Deok Bae

    2007-01-01

    Full Text Available We present a new subband affine projection (SAP algorithm for the adaptive acoustic echo cancellation with long echo path delay. Generally, the acoustic echo canceller suffers from the long echo path and large computational complexity. To solve this problem, the proposed algorithm combines merits of the affine projection (AP algorithm and the subband filtering. Convergence speed of the proposed algorithm is improved by the signal-decorrelating property of the orthogonal subband filtering and the weight updating with the prewhitened input signal of the AP algorithm. Moreover, in the proposed algorithms, as applying the polyphase decomposition, the noble identity, and the critical decimation to subband the adaptive filter, the sufficiently decomposed SAP updates the weights of adaptive subfilters without a matrix inversion. Therefore, computational complexity of the proposed method is considerably reduced. In the SAP, the derived weight updating formula for the subband adaptive filter has a simple form as ever compared with the normalized least-mean-square (NLMS algorithm. The efficiency of the proposed algorithm for the colored signal and speech signal was evaluated experimentally.

  2. Echoing Hylas: A Study in Hellenistic and Roman Metapoetics

    NARCIS (Netherlands)

    Heerink, M.

    2015-01-01

    In Echoing Hylas, Mark Heerink argues that the story of Hylas—a famous episode of the Argonauts’ voyage—was used by poets throughout classical antiquity to reflect symbolically on the position of their poetry in the literary tradition. Certain elements of the story, including the characters of Hylas

  3. Numerical experiment with modelled return echo of a satellite

    Indian Academy of Sciences (India)

    Abstract. We have simulated the return echo of a satellite altimeter from a rough ocean surface using an analytical formula and have studied its sensitivity with respect to various oceanic and altimeter parameters. Our numerical expcriment shows that for normally observed significant wave heights (SWFI) the effect of ...

  4. Vibrational echo spectral observables and frequency fluctuations of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 7. Vibrational echo spectral observables and frequency fluctuations of hydration shell water around a fluoride ion from first principles simulations. DEEPAK OJHA AMALENDU CHANDRA. REGULAR ARTICLE Volume 129 Issue 7 July 2017 pp 1069-1080 ...

  5. Spin-Echo Small-Angle Neutron Scattering Development

    NARCIS (Netherlands)

    Uca, O.

    2003-01-01

    Spin-Echo Small-Angle Neutron Scattering (SESANS) instrument is a novel SANS technique which enables one to characterize distances from a few nanometers up to the micron range. The most striking difference between normal SANS and SESANS is that in SESANS one gets information in real space, whereas

  6. Characteristics of spondylotic myelopathy on 3D driven-equilibrium fast spin echo and 2D fast spin echo magnetic resonance imaging: a retrospective cross-sectional study.

    Science.gov (United States)

    Abdulhadi, Mike A; Perno, Joseph R; Melhem, Elias R; Nucifora, Paolo G P

    2014-01-01

    In patients with spinal stenosis, magnetic resonance imaging of the cervical spine can be improved by using 3D driven-equilibrium fast spin echo sequences to provide a high-resolution assessment of osseous and ligamentous structures. However, it is not yet clear whether 3D driven-equilibrium fast spin echo sequences adequately evaluate the spinal cord itself. As a result, they are generally supplemented by additional 2D fast spin echo sequences, adding time to the examination and potential discomfort to the patient. Here we investigate the hypothesis that in patients with spinal stenosis and spondylotic myelopathy, 3D driven-equilibrium fast spin echo sequences can characterize cord lesions equally well as 2D fast spin echo sequences. We performed a retrospective analysis of 30 adult patients with spondylotic myelopathy who had been examined with both 3D driven-equilibrium fast spin echo sequences and 2D fast spin echo sequences at the same scanning session. The two sequences were inspected separately for each patient, and visible cord lesions were manually traced. We found no significant differences between 3D driven-equilibrium fast spin echo and 2D fast spin echo sequences in the mean number, mean area, or mean transverse dimensions of spondylotic cord lesions. Nevertheless, the mean contrast-to-noise ratio of cord lesions was decreased on 3D driven-equilibrium fast spin echo sequences compared to 2D fast spin echo sequences. These findings suggest that 3D driven-equilibrium fast spin echo sequences do not need supplemental 2D fast spin echo sequences for the diagnosis of spondylotic myelopathy, but they may be less well suited for quantitative signal measurements in the spinal cord.

  7. Redemption of the "spoiled identity:" the role of HIV-positive individuals in HIV care cascade interventions.

    Science.gov (United States)

    Camlin, Carol S; Charlebois, Edwin D; Geng, Elvin; Semitala, Fred; Wallenta, Jeanna; Getahun, Monica; Kampiire, Leatitia; Bukusi, Elizabeth A; Sang, Norton; Kwarisiima, Dalsone; Clark, Tamara D; Petersen, Maya L; Kamya, Moses R; Havlir, Diane V

    2017-12-01

    The concept of "therapeutic citizenship" has drawn attention to ways in which public testimony, the "story-telling in the public sphere" undertaken by people living with HIV (PLHIV), has shaped the global response to the epidemic. This paper presents qualitative findings from two large studies in eastern Africa that reveal how the advent of population-based HIV testing campaigns and efforts to accelerate antiretroviral "treatment for all" has precipitated a rapidly expanding therapeutic citizenship "project," or social movement. The title of this paper refers to Goffman's original conceptualization of stigma as a social process through which a person's identity is rendered "spoiled." Data were derived from qualitative studies embedded within two clinical trials, Sustainable East African Research in Community Health (SEARCH) (NCT# 01864603) in Kenya and Uganda, and START-ART (NCT# 01810289) in Uganda, which aimed to offer insights into the pathways through which outcomes across the HIV care continuum can be achieved by interventions deployed in the studies, any unanticipated consequences, and factors that influenced implementation. Qualitative in-depth semi-structured interviews were conducted among cohorts of adults in 2014 through 2015; across both studies and time periods, 217 interviews were conducted with 166 individuals. Theoretically informed, team-based analytic approaches were used for the analyses. Narratives from PLHIV, who have not always been conceptualized as actors but rather usually as targets of HIV interventions, revealed strongly emergent themes related to these individuals' use of HIV biomedical resources and discourses to fashion a new, empowered subjecthood. Experiencing the benefits of antiretroviral therapy (ART) emboldens many individuals to transform their "spoiled" identities to attain new, valorized identities as "advocates for ART" in their communities. We propose that the personal revelation of what some refer to as the "gospel of ARVs

  8. The electron capture in 163Ho experiment - ECHo

    Science.gov (United States)

    Gastaldo, L.; Blaum, K.; Chrysalidis, K.; Day Goodacre, T.; Domula, A.; Door, M.; Dorrer, H.; Düllmann, Ch. E.; Eberhardt, K.; Eliseev, S.; Enss, C.; Faessler, A.; Filianin, P.; Fleischmann, A.; Fonnesu, D.; Gamer, L.; Haas, R.; Hassel, C.; Hengstler, D.; Jochum, J.; Johnston, K.; Kebschull, U.; Kempf, S.; Kieck, T.; Köster, U.; Lahiri, S.; Maiti, M.; Mantegazzini, F.; Marsh, B.; Neroutsos, P.; Novikov, Yu. N.; Ranitzsch, P. C. O.; Rothe, S.; Rischka, A.; Saenz, A.; Sander, O.; Schneider, F.; Scholl, S.; Schüssler, R. X.; Schweiger, Ch.; Simkovic, F.; Stora, T.; Szücs, Z.; Türler, A.; Veinhard, M.; Weber, M.; Wegner, M.; Wendt, K.; Zuber, K.

    2017-06-01

    Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the 3H β-decay and the 163Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in 163Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide 163Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the 163Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure 163Ho samples, the identification and suppression of background sources as well as the precise parametrization of the 163Ho EC spectrum are of utmost importance. The high-energy resolution 163Ho spectra measured with the first MMC prototypes with ion-implanted 163Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq 163Ho will allow to reach a neutrino mass sensitivity below 10 eV/ c 2. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq 163Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass.

  9. Neutron resonance spin echo with longitudinal DC fields

    Science.gov (United States)

    Krautloher, Maximilian; Kindervater, Jonas; Keller, Thomas; Häußler, Wolfgang

    2016-12-01

    We report on the design, construction, and performance of a neutron resonance spin echo (NRSE) instrument employing radio frequency (RF) spin flippers combining RF fields with DC fields, the latter oriented parallel (longitudinal) to the neutron propagation direction (longitudinal NRSE (LNRSE)). The advantage of the longitudinal configuration is the inherent homogeneity of the effective magnetic path integrals. In the center of the RF coils, the sign of the spin precession phase is inverted by a π flip of the neutron spins, such that non-uniform spin precession at the boundaries of the RF flippers is canceled. The residual inhomogeneity can be reduced by Fresnel- or Pythagoras-coils as in the case of conventional spin echo instruments (neutron spin echo (NSE)). Due to the good intrinsic homogeneity of the B0 coils, the current densities required for the correction coils are at least a factor of three less than in conventional NSE. As the precision and the current density of the correction coils are the limiting factors for the resolution of both NSE and LNRSE, the latter has the intrinsic potential to surpass the energy resolution of present NSE instruments. Our prototype LNRSE spectrometer described here was implemented at the resonance spin echo for diverse applications (RESEDA) beamline at the MLZ in Garching, Germany. The DC fields are generated by B0 coils, based on resistive split-pair solenoids with an active shielding for low stray fields along the beam path. One pair of RF flippers at a distance of 2 m generates a field integral of ˜0.5 Tm. The LNRSE technique is a future alternative for high-resolution spectroscopy of quasi-elastic excitations. In addition, it also incorporates the MIEZE technique, which allows to achieve spin echo resolution for spin depolarizing samples and sample environments. Here we present the results of numerical optimization of the coil geometry and first data from the prototype instrument.

  10. Improving Pain Care with Project ECHO in Community Health Centers.

    Science.gov (United States)

    Anderson, Daren; Zlateva, Ianita; Davis, Bennet; Bifulco, Lauren; Giannotti, Tierney; Coman, Emil; Spegman, Douglas

    2017-10-01

    Pain is an extremely common complaint in primary care, and patient outcomes are often suboptimal. This project evaluated the impact of Project ECHO Pain videoconference case-based learning sessions on knowledge and quality of pain care in two Federally Qualified Health Centers. Quasi-experimental, pre-post intervention, with comparison group. Two large, multisite federally qualified health centers in Connecticut and Arizona. Intervention (N = 10) and comparison (N = 10) primary care providers. Primary care providers attended 48 weekly Project ECHO Pain sessions between January and December 2013, led by a multidisciplinary pain specialty team. Surveys and focus groups assessed providers' pain-related knowledge and self-efficacy. Electronic health record data were analyzed to evaluate opioid prescribing and specialty referrals. Compared with control, primary care providers in the intervention had a significantly greater increase in pain-related knowledge and self-efficacy. Providers who attended ECHO were more likely to use formal assessment tools and opioid agreements and refer to behavioral health and physical therapy compared with control providers. Opioid prescribing decreased significantly more among providers in the intervention compared with those in the control group. Pain is an extremely common and challenging problem, particularly among vulnerable patients such as those cared for at the more than 1,200 Federally Qualified Health Centers in the United States. In this study, attendance at weekly Project ECHO Pain sessions not only improved knowledge and self-efficacy, but also altered prescribing and referral patterns, suggesting that knowledge acquired during ECHO sessions translated into practice changes. © 2017 American Academy of Pain Medicine.

  11. Duel frequency echo data acquisition system for sea-floor classification

    Digital Repository Service at National Institute of Oceanography (India)

    Navelkar, G.S.; Desai, R.G.P.; Chakraborty, B.

    An echo data acquisition system is designed to digitize echo signal from a single beam shipboard echo-sounder for use in sea-floor classification studies using a 12 bit analog to digital (A/D) card with a maximum sampling frequency of 1 MHz. Both 33...

  12. Slice accelerated gradient-echo spin-echo dynamic susceptibility contrast imaging with blipped CAIPI for increased slice coverage.

    Science.gov (United States)

    Eichner, Cornelius; Jafari-Khouzani, Kourosh; Cauley, Stephen; Bhat, Himanshu; Polaskova, Pavlina; Andronesi, Ovidiu C; Rapalino, Otto; Turner, Robert; Wald, Lawrence L; Stufflebeam, Steven; Setsompop, Kawin

    2014-09-01

    To improve slice coverage of gradient echo spin echo (GESE) sequences for dynamic susceptibility contrast (DSC) MRI using a simultaneous-multiple-slice (SMS) method. Data were acquired on 3 Tesla (T) MR scanners with a 32-channel head coil. To evaluate use of SMS for DSC, an SMS GESE sequence with two-fold slice coverage and same temporal sampling was compared with a standard GESE sequence, both with 2× in-plane acceleration. A signal to noise ratio (SNR) comparison was performed on one healthy subject. Additionally, data with Gadolinium injection were collected on three patients with glioblastoma using both sequences, and perfusion analysis was performed on healthy tissues as well as on tumor. Retained SNR of SMS DSC is 90% for a gradient echo (GE) and 99% for a spin echo (SE) acquisition, compared with a standard acquisition without slice acceleration. Comparing cerebral blood volume maps, it was observed that the results of standard and SMS acquisitions are comparable for both GE and SE images. Two-fold slice accelerated DSC MRI achieves similar SNR and perfusion metrics as a standard acquisition, while allowing a significant increase in slice coverage of the brain. The results also point to a possibility to improve temporal sampling rate, while retaining the same slice coverage. Copyright © 2013 Wiley Periodicals, Inc.

  13. Rehabilitation of semi-arid coal mine spoil bank soils with mine residues and farm organic by-products

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.; Bosch-Serra, A.; Estudillos, G.; Poch, R.M. [University of Lleida, Lleida (Spain). Dept. of Environmental & Soil Science

    2009-07-01

    A method of rehabilitating coal mine soils was studied under the conditions of a semi-arid climate, lack of topsoil but availability of farm by-products in NE Spain. The objectives of the research were to assess a new method in order to achieve a suitable substrate for the establishment of native vegetation, to evaluate environmental impacts associated with the reclamation process, and to determine the time necessary to integrate the treated area into the surrounding environment. Eight plots (10 x 35 m{sup 2}) were established in September 1997. Substrate combinations of two types of mine spoil (coal dust and coarse-sized material), two levels of pig slurry (39 and 94 Mg ha{sup -1}dry-wt), and cereal straw (0 and 15 Mg ha{sup -1}) were applied. Monitoring of select physical and chemical soil properties and vegetation characteristics was performed from 1997 until 2005. The bulk density and the saturated hydraulic conductivity measured did not limit plant development and water availability. Initial substrate salinity (1.37 S m{sup -1}) decreased with time and in the long term did not limit plant colonization to salinity-adapted species. Initial nitrate concentration was 298 mg kg{sup -1}, but was reduced significantly to acceptable values in 3 years (55 mg kg{sup -1}) and the measured pH (7.6) was maintained at the level of initial spoil values. Vegetation cover reached up to 90%. In the treated area, spontaneous vegetation cover (15 to 70%) colonized the nonsown areas widely. In the medium term, vegetation cover tended to be higher in plots with a thicker layer of coal dust material and the higher slurry rate. Soil rehabilitation and environmental reintegration, taking into account soil and vegetation indicators, was possible in the studied area with low cost inputs using residual materials from mining activities and animal husbandry by-products.

  14. MR contrast of ferritin and hemosiderin in the brain: comparison among gradient-echo, conventional spin-echo and fast spin-echo sequences

    Energy Technology Data Exchange (ETDEWEB)

    Haque, Tabassum Laz; Miki, Yukio E-mail: mikiy@kuhp.kyoto-u.ac.jp; Kanagaki, Mitsunori; Takahashi, Takahiro; Yamamoto, Akira; Konishi, Junya; Nozaki, Kazuhiko; Hashimoto, Nobuo; Konishi, Junji

    2003-12-01

    Objective: To compare the magnetic resonance image contrasts due to ferritin and hemosiderin in the brain tissue among different pulse sequences. Materials and methods: Fourteen patients with cavernous hemangioma in the brain prospectively underwent MR imaging with T2*-weighted gradient-echo (GRE), T2-weighted conventional spin-echo (SE) and fast spin-echo (FSE) sequences. The relative contrast ratios (CRs) of the hypointense part of cavernous hemangioma, globus pallidus and putamen to the deep frontal white matter were measured on each pulse sequence and statistically analyzed using analysis of variance followed by paired t-test. Results: In the hypointense part of cavernous hemangioma, relative CRs were significantly lower on T2*-weighted GRE than on T2-weighted SE images (P=0.0001), and on T2-weighted SE than on T2-weighted FSE images (P=0.0001). In the globus pallidus, relative CRs were significantly lower on T2-weighted SE than on T2*-weighted GRE images (P=0.002), and on T2*-weighted GRE than on T2-weighted FSE images (P=0.0002). In the putamen, relative CRs were significantly lower on T2-weighted SE than on T2*-weighted GRE images (P=0.001), and there was no significant difference between CRs on T2-weighted FSE and T2*-weighted GRE images (P=0.90). Conclusion: Hemosiderin showed best image contrast on T2*-weighted GRE images but ferritin showed more prominent image contrast on T2-weighted SE than on T2*-weighted GRE images, which may help to determine an appropriate pulse sequence in neurological diseases associated with excessive ferritin accumulation.

  15. MR contrast of ferritin and hemosiderin in the brain: comparison among gradient-echo, conventional spin-echo and fast spin-echo sequences.

    Science.gov (United States)

    Haque, Tabassum Laz; Miki, Yukio; Kanagaki, Mitsunori; Takahashi, Takahiro; Yamamoto, Akira; Konishi, Junya; Nozaki, Kazuhiko; Hashimoto, Nobuo; Konishi, Junji

    2003-12-01

    To compare the magnetic resonance image contrasts due to ferritin and hemosiderin in the brain tissue among different pulse sequences. Fourteen patients with cavernous hemangioma in the brain prospectively underwent MR imaging with T2*-weighted gradient-echo (GRE), T2-weighted conventional spin-echo (SE) and fast spin-echo (FSE) sequences. The relative contrast ratios (CRs) of the hypointense part of cavernous hemangioma, globus pallidus and putamen to the deep frontal white matter were measured on each pulse sequence and statistically analyzed using analysis of variance followed by paired t-test. In the hypointense part of cavernous hemangioma, relative CRs were significantly lower on T2*-weighted GRE than on T2-weighted SE images (P=0.0001), and on T2-weighted SE than on T2-weighted FSE images (P=0.0001). In the globus pallidus, relative CRs were significantly lower on T2-weighted SE than on T2*-weighted GRE images (P=0.002), and on T2*-weighted GRE than on T2-weighted FSE images (P=0.0002). In the putamen, relative CRs were significantly lower on T2-weighted SE than on T2*-weighted GRE images (P=0.001), and there was no significant difference between CRs on T2-weighted FSE and T2*-weighted GRE images (P=0.90). Hemosiderin showed best image contrast on T2*-weighted GRE images but ferritin showed more prominent image contrast on T2-weighted SE than on T2*-weighted GRE images, which may help to determine an appropriate pulse sequence in neurological diseases associated with excessive ferritin accumulation.

  16. Focal liver lesion detection and characterization: Comparison of non-contrast enhanced and SPIO-enhanced diffusion-weighted single-shot spin echo echo planar and turbo spin echo T2-weighted imaging

    NARCIS (Netherlands)

    Coenegrachts, Kenneth; Matos, Celso; ter Beek, Léon; Metens, Thierry; Haspeslagh, Marc; Bipat, Shandra; Stoker, Jaap; Rigauts, Hans

    2009-01-01

    Purpose: To compare lesion conspicuity and image quality between single-shot spin echo echo planar imaging (SS SE-EPI) before, immediately and 5 min after intravenous (IV) injection of superparamagnetic iron oxide (SPIO) for detecting and characterizing focal liver lesions (FLLs). Materials and

  17. Prospects for Precise Measurements with Echo Atom Interferometry

    Directory of Open Access Journals (Sweden)

    Brynle Barrett

    2016-06-01

    Full Text Available Echo atom interferometers have emerged as interesting alternatives to Raman interferometers for the realization of precise measurements of the gravitational acceleration g and the determination of the atomic fine structure through measurements of the atomic recoil frequency ω q . Here we review the development of different configurations of echo interferometers that are best suited to achieve these goals. We describe experiments that utilize near-resonant excitation of laser-cooled rubidium atoms by a sequence of standing wave pulses to measure ω q with a statistical uncertainty of 37 parts per billion (ppb on a time scale of ∼50 ms and g with a statistical precision of 75 ppb. Related coherent transient techniques that have achieved the most statistically precise measurements of atomic g-factor ratios are also outlined. We discuss the reduction of prominent systematic effects in these experiments using off-resonant excitation by low-cost, high-power lasers.

  18. Efficient Multichannel NLMS Implementation for Acoustic Echo Cancellation

    Directory of Open Access Journals (Sweden)

    Schüldt Christian

    2007-01-01

    Full Text Available An acoustic echo cancellation structure with a single loudspeaker and multiple microphones is, from a system identification perspective, generally modelled as a single-input multiple-output system. Such a system thus implies specific echo-path models (adaptive filter for every loudspeaker to microphone path. Due to the often large dimensionality of the filters, which is required to model rooms with standard reverberation time, the adaptation process can be computationally demanding. This paper presents a selective updating normalized least mean square (NLMS-based method which reduces complexity to nearly half in practical situations, while showing superior convergence speed performance as compared to conventional complexity reduction schemes. Moreover, the method concentrates the filter adaptation to the filter which is most misadjusted, which is a typically desired feature.

  19. Efficient Multichannel NLMS Implementation for Acoustic Echo Cancellation

    Directory of Open Access Journals (Sweden)

    Fredric Lindstrom

    2007-02-01

    Full Text Available An acoustic echo cancellation structure with a single loudspeaker and multiple microphones is, from a system identification perspective, generally modelled as a single-input multiple-output system. Such a system thus implies specific echo-path models (adaptive filter for every loudspeaker to microphone path. Due to the often large dimensionality of the filters, which is required to model rooms with standard reverberation time, the adaptation process can be computationally demanding. This paper presents a selective updating normalized least mean square (NLMS-based method which reduces complexity to nearly half in practical situations, while showing superior convergence speed performance as compared to conventional complexity reduction schemes. Moreover, the method concentrates the filter adaptation to the filter which is most misadjusted, which is a typically desired feature.

  20. Spin-echo entanglement protection from random telegraph noise

    Science.gov (United States)

    Lo Franco, R.; D'Arrigo, A.; Falci, G.; Compagno, G.; Paladino, E.

    2013-03-01

    We analyze local spin-echo procedures for protecting entanglement between two non-interacting qubits, each subject to pure-dephasing random telegraph noise. For superconducting qubits, this simple model captures the characteristic features of the effect of bistable impurities coupled to the device. An analytic expression for the entanglement dynamics is reported. Peculiar features related to the non-Gaussian nature of the noise already observed in the single-qubit dynamics also occur in the entanglement dynamics for proper values of the ratio g = v/γ, between the qubit-impurity coupling strength and the switching rate of the random telegraph process, and of the separation between the pulses Δt. We found that the echo procedure may delay the disappearance of entanglement, cancel the dynamical structure of entanglement revivals and dark periods and induce peculiar plateau-like behaviors of the concurrence.

  1. Birefringent neutron prisms for spin echo scattering angle measurement

    Science.gov (United States)

    Pynn, Roger; Fitzsimmons, M. R.; Lee, W. T.; Stonaha, P.; Shah, V. R.; Washington, A. L.; Kirby, B. J.; Majkrzak, C. F.; Maranville, B. B.

    2009-09-01

    In the first decade of the 19th century, an English chemist, William Wollaston, invented an arrangement of birefringent prisms that splits a beam of light into two spatially separated beams with orthogonal polarizations. We have constructed similar devices for neutrons using triangular cross-section solenoids and employed them for Spin Echo Scattering Angle Measurement (SESAME). A key difference between birefringent neutron prisms and their optical analogues is that it is hard to embed the former in a medium which has absolutely no birefringence because this implies the removal of all magnetic fields. We have overcome this problem by using the symmetry properties of the Wollaston neutron prisms and of the overall spin echo arrangement. These symmetries cause a cancellation of Larmor phase aberrations and provide robust coding of neutron scattering angles with simple equipment.

  2. CORRELATIONS BETWEEN HAIL EVENTS AND RADAR ECHOES IN TRANSYLVANIA

    Directory of Open Access Journals (Sweden)

    RECKERTH U. D.

    2015-03-01

    Full Text Available Over 500 hail events reported across Transylvania by meteorological and hydrological stations, with several large hail events (i.e. hail diameter ≥ 2 cm, were studied during 2004-2014. The purpose of this study was to determine the correlations between the hail events, especially the hail size, and different radar echoes, such as reflectivity, vertically integrated liquid, echo tops of the clouds, and instability indices, such as the vertical totals index, in order to provide useful information regarding forecast of hail, especially large hail. The radar data were measured by the WSR-98D Doppler radar from Bobohalma-Tarnaveni, Mures county, placed in central Transylvania. I have also studied the use of vertically integrated liquid density as an indicator for the size of hail in thunderstorms, applied in Transylvania for operational use. The methodology used in deriving this comparison is provided to assist other operational weather forecasters in developing VIL Density vs. hail size correlation.

  3. Inaudible functional MRI using a truly mute gradient echo sequence

    Energy Technology Data Exchange (ETDEWEB)

    Marcar, V.L. [University of Zurich, Department of Psychology, Neuropsychology, Treichlerstrasse 10, 8032 Zurich (Switzerland); Girard, F. [GE Medical Systems SA, 283, rue de la Miniere B.P. 34, 78533 Buc Cedex (France); Rinkel, Y.; Schneider, J.F.; Martin, E. [University Children' s Hospital, Neuroradiology and Magnetic Resonance, Department of Diagnostic Imaging, Steinwiesstrasse 75, 8032 Zurich (Switzerland)

    2002-11-01

    We performed functional MRI experiments using a mute version of a gradient echo sequence on adult volunteers using either a simple visual stimulus (flicker goggles: 4 subjects) or an auditory stimulus (music: 4 subjects). Because the mute sequence delivers fewer images per unit time than a fast echo planar imaging (EPI) sequence, we explored our data using a parametric ANOVA test and a non-parametric Wilcoxon-Mann-Whitney test in addition to performing a cross-correlation analysis. All three methods were in close agreement regarding the location of the BOLD contrast signal change. We demonstrated that, using appropriate statistical analysis, functional MRI using an MR sequence that is acoustically inaudible to the subject is feasible. Furthermore compared with the ''silent'' event-related procedures involving an EPI protocol, our mGE protocol compares favourably with respect to experiment time and the BOLD signal. (orig.)

  4. Benefits of the Multiple Echo Technique for Ultrasonic Thickness Testing

    Energy Technology Data Exchange (ETDEWEB)

    Elder, J.; Vandekamp, R.

    2011-02-10

    Much effort has been put into determining methods to make accurate thickness measurements, especially at elevated temperatures. An accuracy of +/- 0.001 inches is typically noted for commercial ultrasonic thickness gauges and ultrasonic thickness techniques. Codes and standards put limitations on many inspection factors including equipment, calibration tolerance and temperature variations. These factors are important and should be controlled, but unfortunately do not guarantee accurate and repeatable measurements in the field. Most technicians long for a single technique that is best for every situation, unfortunately, there are no 'silver bullets' when it comes to nondestructive testing. This paper will describe and discuss some of the major contributors to measurement error as well as some advantages and limitations of multiple echo techniques and why multiple echo techniques should be more widely utilized for ultrasonic thickness measurements.

  5. Stimulated nuclear spin echos and spectral diffusion in glasses

    International Nuclear Information System (INIS)

    Borges, N.M.; Engelsberg, M.

    1984-01-01

    Experimental results of stimulated nuclear spin echos decay in glasses are presented. The measurements were performed in B 2 O 3 glasses, at the 23Na and 11 B resonance lines. The data analysis allows the study of Spectral diffusion at an inhomogeneous nuclear magnetic (NMR) resonance line, broadened for a desordered system of nuclear spins. A model is proposed to explain the time constants, and the particular form of the decay. (A.C.A.S.) [pt

  6. Ultra-short echo time images quantify high liver iron.

    Science.gov (United States)

    Doyle, Eamon K; Toy, Kristin; Valdez, Bertin; Chia, Jonathan M; Coates, Thomas; Wood, John C

    2018-03-01

    1.5T gradient echo-based R2∗ estimates are standard-of-care for assessing liver iron concentration (LIC). Despite growing popularity of 3T, echo time (TE) limitations prevent 3T liver iron quantitation in the upper half of the clinical range (LIC ⪆20 mg/g). In this work, a 3D radial pulse sequence was assessed to double the dynamic range of 3T LIC estimates. The minimum TE limits the dynamic range of pulse sequences to estimate R2∗. 23 chronically-transfused human volunteers were imaged with 1.5T Cartesian gradient echo (1.5T-GRE), 3T Cartesian gradient echo (3T-GRE), and 3T ultrashort TE radial (3T-UTE) pulse sequences; minimum TEs were 0.96, 0.76, and 0.19 ms, respectively. R2∗ was estimated with an exponential signal model, normalized to 1.5T equivalents, and converted to LIC. Bland-Altman analysis compared 3T-based estimates to 1.5T-GRE. LIC by 3T-GRE was unbiased versus 1.5T-GRE for LIC ≤ 25 mg/g (sd = 9.6%); 3T-GRE failed to quantify LIC > 25 mg/g. At high iron loads, 3T-UTE was unbiased (sd = 14.5%) compared to 1.5T-GRE. Further, 3T-UTE estimated LIC up to 50 mg/g, exceeding 1.5T-GRE limits. 3T-UTE imaging can reliably estimate high liver iron burdens. In conjunction with 3T-GRE, 3T-UTE allows clinical LIC estimation across a wide range of liver iron loads. Magn Reson Med 79:1579-1585, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  7. RESPECT: Neutron resonance spin-echo spectrometer for extreme studies

    Energy Technology Data Exchange (ETDEWEB)

    Georgii, R., E-mail: Robert.Georgii@frm2.tum.de [Physik-Department, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany); Heinz Maier-Leibnitz Zentrum, Technische Universität München, Lichtenbergstr. 1, D-85748 Garching (Germany); Kindervater, J. [Physik-Department, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany); Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street Baltimore, MD 21218 (United States); Pfleiderer, C.; Böni, P. [Physik-Department, Technische Universität München, James-Franck-Str. 1, D-85748 Garching (Germany)

    2016-11-21

    We propose the design of a REsonance SPin-echo spECtrometer for exTreme studies, RESPECT, that is ideally suited for the exploration of non-dispersive processes such as diffusion, crystallization, slow dynamics, tunneling processes, crystal electric field excitations, and spin fluctuations. It is a variant of the conventional neutron spin-echo technique (NSE) by (i) replacing the long precession coils by pairs of longitudinal neutron spin-echo coils combined with RF-spin flippers and (ii) by stabilizing the neutron polarization with small longitudinal guide fields that can in addition be used as field subtraction coils thus allowing to adjust the field integrals over a range of 8 orders of magnitude. Therefore, the dynamic range of RESPECT can in principle be varied over 8 orders of magnitude in time, if neutrons with the required energy are made available. Similarly as for existing NSE-spectrometers, spin echo times of up to approximately 1 μs can be reached if the divergence and the correction elements are properly adjusted. Thanks to the optional use of neutron guides and the fact that the currents for the correction coils are much smaller than in standard NSE, intensity gains of at least one order of magnitude are expected, making the concept of RESPECT also competitive for operation at medium flux neutron sources. RESPECT can also be operated in a MIEZE configuration allowing the investigation of relaxation processes in depolarizing environments as they occur when magnetic fields are applied at the sample position, i.e. for the investigation of the dynamics of flux lines in superconductors, magnetic fluctuations in ferromagnetic materials, and samples containing hydrogen.

  8. CUTLASS HF radar observations of high-velocity E-region echoes

    Directory of Open Access Journals (Sweden)

    M. V. Uspensky

    2001-04-01

    Full Text Available A short event of high-velocity E-region echo observations by the Pykkvibaer HF radar is analysed to study echo parameters and the echo relation to the Farley-Buneman plasma instability. The echoes were detected in several beams aligned closely to the magnetic L-shell direction. Two echo groups were identified: one group corresponded to the classical type 1 echoes with velocities close to the nominal ion-acoustic speed of 400 ms–1 , while the other group had significantly larger velocities, of the order of 700 ms–1 . The mutual relationship between the echo power, Doppler velocity, spectral width and elevation angles for these two groups was studied. Plotting of echo parameters versus slant range showed that all ~700 ms–1 echoes originated from larger heights and distances of 500–700 km, while all ~400 ms–1 echoes came from lower heights and from farther distances; 700–1000 km. We argue that both observed groups of echoes occurred due to the Farley-Buneman plasma instability excited by strong ( ~70 mVm–1 and uniformly distributed electric fields. We show that the echo velocities for the two groups were different because the echoes were received from different heights. Such a separation of echo heights occurred due to the differing amounts of ionospheric refraction at short and large ranges. Thus, the ionospheric refraction and related altitude modulation of ionospheric parameters are the most important factors to consider, when various characteristics of E-region decametre irregularities are derived from HF radar measurements.Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; polar ionosphere

  9. Climatology and variability in the ECHO coupled GCM

    International Nuclear Information System (INIS)

    Latif, M.; Stockdale, T.; Wolff, J.; Burgers, G.; Maier-Reimer, E.; Junge, M.M.; Arpe, K.; Bengtsson, L.

    1993-01-01

    ECHO is a new global coupled ocean-atmosphere general circulation model (GCM), consisting of the Hamburg version of the European Centre atmospheric GCM (ECHAM) and the Hamburg Primitive Equation ocean GCM (HOPE). We performed a twenty year integration with ECHO. Climate drift is significant, but typical in the open oceans. Near the boundaries, however, SST errors are considerably larger. The coupled model simulates an irregular ENSO cycle in the tropical Pacific, with spatial patterns similar to those observed. The mechanism behind the model ENSO is related to the subsurface memory of the system, but stochastic forcing by the atmosphere seems to be also important. The variability, however, is somewhat weaker relative to observations. ECHO also simulates significant interannual variability in midlatitudes. Consistent with observations, variability over the North Pacific can be partly attributed to remote forcing from the tropics. In contract, the interannual variability over the North Atlantic appears to be generated locally. Indications for decadal-scale variability are also found over the North Atlantic. (orig.)

  10. Head echoes and solar activity in the geminid period

    International Nuclear Information System (INIS)

    Pecina, P.

    1975-01-01

    The occurrence of head echoes in dependence on solar activity in the Geminid period 1959-1969 is examined. All considerations refer to the interval 22sup(h)-06sup(h) U.T. Solar ionizing radiation is assumed to be either X-ray and ultraviolet, or corpuscular radiation. The former is characterized by the correlated solar microwave flux F, and the latter by Asub(p) and Ksub(p) indices. A comparison of the variations with solar longitude of the indices and of relative head echo rates on the days of observation is not possible for every year. A comparison within the 11-year solar cycle does not lead to the conclusion that in the interval 22sup(h)-06sup(h) U.T. it is the corpuscular radiation that determines the head echo phenomenon. A definite answer to the question of the nature of effective radiation will be possible when radar observations for more solar cycles and a longer time interval are available. (author)

  11. Cerebral microhemorrhage : assessment with gradient-echo Mr

    International Nuclear Information System (INIS)

    Kim, Eung Yeop; Na, Dong Gyu; Byun, Hong Sik; Shin, Myung Hee

    1998-01-01

    The purpose of this study is to assess the relationship between low signal intensity lesions, as seen on gradient-echo MR, and clinical factors. In 269 patients with cerebral ischemic symptoms, we analysed the results of gradient-echo MR. One hundred and thirty-nine of the patients were male and 130 were female; their ages ranged from 40 to 88 (mean, 64) years. Low signal intensity lesions were analyzed according to the dominant location ; superficial (cortex and subcortical white matter) or deep (basal ganglia, thalamus, periventricular white matter, and cerebellum). We analyzed the relationship between low signal intensity lesions and clinical factors including hypertension, diabetes mellitus (DM), and spontaneous intracerebral hemorrhage (ICH). Low signal intensity lesions were found in 66 of 269 patients (25%); hypertension was present in 57 of the 66 (86%, p 0.05), and spontaneous ICH in 26 (39 %, p<0.05). The dominant location of these lesions was superficial (n=19), deep (n=45), or both (n=2). Hypertension was deep. Hypertension was not present in nine of 66 patients (14%) with low signal intensity lesions; in six of these (66%), low signal intensity lesions were present mainly in the subcortical white matter or cortex. Cerebral low signal intensity lesions, as seen on gradient-echo MR imaging were associated with clinical factors such as hypertension and spontaneous ICH, and hypertension was more frequently found in patients in whom the location of low signal intensity lesions was deep. (author). 19 refs., 1 tab., 3 figs

  12. Three-Dimensional Processing of Ultrasonic Pulse-Echo Signal

    International Nuclear Information System (INIS)

    Song, Moon Ho; Song, Sang Rock; Cho, Jung Ho; Sung, Je Joong; Ahn, Hyung Keun; Jang, Soon Jae

    2003-01-01

    Ultrasonic imaging of 3-D structures for nondestructive evaluation must provide readily recognizable images with enough details to clearly show various flaws that may or may not be present. Typical flaws that need to be detected are miniature cracks, for instance, in metal pipes having aged over years of operation in nuclear power plants; and these sub-millimeter cracks or flaws must be depicted in the final 3-D image for a meaningful evaluation. As a step towards improving conspicuity and thus detection of flaws, we propose a pulse-echo ultrasonic imaging technique to generate various 3-D views of the 3-D object under evaluation through strategic scanning and processing of the pulse-echo data. We employ a 2-D Wiener filter that filters the pulse-echo data along the plane orthogonal to the beam propagation so that ultrasonic beams can be sharpened. This three-dimensional processing and display coupled with 3-D manipulation capabilities by which users are able to pan and rotate the 3-D structure improve conspicuity of flaws. Providing such manipulation operations allow a clear depiction of the size and the location of various flaws in 3-D

  13. MR fingerprinting using the quick echo splitting NMR imaging technique.

    Science.gov (United States)

    Jiang, Yun; Ma, Dan; Jerecic, Renate; Duerk, Jeffrey; Seiberlich, Nicole; Gulani, Vikas; Griswold, Mark A

    2017-03-01

    The purpose of the study is to develop a quantitative method for the relaxation properties with a reduced radio frequency (RF) power deposition by combining magnetic resonance fingerprinting (MRF) technique with quick echo splitting NMR imaging technique (QUEST). A QUEST-based MRF sequence was implemented to acquire high-order echoes by increasing the gaps between RF pulses. Bloch simulations were used to calculate a dictionary containing the range of physically plausible signal evolutions using a range of T 1 and T 2 values based on the pulse sequence. MRF-QUEST was evaluated by comparing to the results of spin-echo methods. The specific absorption rate (SAR) of MRF-QUEST was compared with the clinically available methods. MRF-QUEST quantifies the relaxation properties with good accuracy at the estimated head SAR of 0.03 W/kg. T 1 and T 2 values estimated by MRF-QUEST are in good agreement with the traditional methods. The combination of the MRF and the QUEST provides an accurate quantification of T 1 and T 2 simultaneously with reduced RF power deposition. The resulting lower SAR may provide a new acquisition strategy for MRF when RF energy deposition is problematic. Magn Reson Med 77:979-988, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  14. Depolarization of neutron spin echo by magnetic fluid

    International Nuclear Information System (INIS)

    Achiwa, N.; Sirozu, G.; Nishioka, T.; Ebisawa, T.; Hino, M.; Tasaki, S.; Kawai, T.; Yamazaki, D.

    2001-01-01

    A new method to study the fluctuations of magnetization in magnetic fluids by measuring relations between the phase shift of Larmor precession and the visibility of the neutron spin echo caused by the change of flight path length is studied. Magnetic fluid in which fine particles of magnetite of about 10 nm diameters coated with oleic acid and suspended in water was used. Thickness of the sample was 2 mm. In the dynamics of magnetic fluids, Brownian motions of colloids and the thermal fluctuations of magnetization known as the superparamagnetism are dominant. Isolated ferromagnetic particles of the present size are superparamagnetic but they aggregate to form clusters in a weak magnetic field in the sample of 40% weight density. When neutrons pass the sample, spins process in the magnetic flux density of the clusters fluctuating in time and space. Consequently the Larmor precession phases become distributed and the quantization axes are fluctuated. The result is observed as a decrease of the visibility of the spin echo signals. The change of magnetic flux density in the magnetic fluid is measured from the change of echo visibility of the neutrons, vice versa. In the present experiment, echo was measured at q=0. It is observed that the phase shift changes as a quadratic function of the sample angle reflecting the change of the path length through the sample. Since the number of Larmor precession is proportional to the product of the magnetic field and the length of the flight path, mean flux density in the magnetic fluid is calculated from the phase shift. On the other hand, the decrease of the spin echo amplitude as the function of the sample angle reflects the time and space fluctuations of the flux density in the sample. If the direction of the magnetic flux density vector (quantization axis) changes slowly enough compared to the Larmor precession period while a neutron passes one magnetic domain, the neutron spin rotation in the domain is given by the spin

  15. A new technique for MR elastography of the supraspinatus muscle: A gradient-echo type multi-echo sequence.

    Science.gov (United States)

    Ito, Daiki; Numano, Tomokazu; Mizuhara, Kazuyuki; Takamoto, Koichi; Onishi, Takaaki; Nishijo, Hisao

    2016-10-01

    Magnetic resonance elastography (MRE) can measure tissue stiffness quantitatively and noninvasively. Supraspinatus muscle injury is a significant problem among throwing athletes. The purpose of this study was to develop an MRE technique for application to the supraspinatus muscle by using a conventional magnetic resonance imaging (MRI). MRE acquisitions were performed with a gradient-echo type multi-echo MR sequence at 100Hz pneumatic vibration. A custom-designed vibration pad was used as a pneumatic transducer in order to adapt to individual shoulder shapes. In a gradient-echo type multi-echo MR sequence, without motion encoding gradient (MEG) that synchronizes with vibrations, bipolar readout gradient lobes achieved a similar function to MEG (MEG-like effect). In other words, a dedicated MRE sequence (built-in MEG) is not always necessary for MRE. In this study, 7 healthy volunteers underwent MRE. We investigated the effects of direction of the MEG-like effect and selected imaging planes on the patterns of wave propagation (wave image). The results indicated that wave images showed clear wave propagation on a condition that the direction of the MEG-like effect was nearly perpendicular to the long axis of the supraspinatus muscle, and that the imaging plane was superior to the proximal supraspinatus muscle. This limited condition might be ascribed to specific features of fibers in the supraspinatus muscle and wave reflection from the boundaries of the supraspinous fossa. The mean stiffness of the supraspinatus muscle was 10.6±3.17kPa. Our results demonstrated that using MRE, our method can be applied to the supraspinatus muscle by using conventional MRI. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. A pilot validation of multi-echo based echo-planar correlated spectroscopic imaging in human calf muscles.

    Science.gov (United States)

    Furuyama, Jon K; Nagarajan, Rajakumar; Roberts, Christian K; Lee, Cathy C; Hahn, Theodore J; Thomas, M Albert

    2014-10-01

    A current limitation of MR spectroscopic imaging of multiple skeletal muscles is prolonged scan duration. A significant reduction in the total scan duration using the echo-planar correlated spectroscopic imaging (EP-COSI) sequence was accomplished using two bipolar readout trains with different phase-encoded echoes for one of two spatial dimensions within a single repetition time (TR). The second bipolar readout was used for spatially encoding the outer k-space, whereas the first readout was used for the central k-space only. The performance of this novel sequence, called multi-echo based echo-planar correlated spectroscopic imaging (ME-EPCOSI), was demonstrated by localizing specific key features in calf muscles and bone marrow of 11 healthy volunteers and five subjects with type 2 diabetes (T2D). A 3 T MRI-MRS scanner equipped with a transmit-receive extremity coil was used. Localization of the ME-EPCOSI sequence was in good agreement with the earlier single-readout based EP-COSI sequence and the required scan time was reduced by a factor of two. In agreement with an earlier report using single-voxel based 2D MRS, significantly increased unsaturated pools of intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) and decreased IMCL and EMCL unsaturation indices (UIs) were observed in the soleus and tibialis anterior muscle regions of subjects with T2D compared with healthy controls. In addition, significantly decreased choline content was observed in the soleus of T2D subjects compared with healthy controls. Multi-voxel characterization of IMCL and EMCL ratios and UI in the calf muscle may be useful for the non-invasive assessment of altered lipid metabolism in the pathophysiology of T2D. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Magnetic resonance imaging of lumbar spine. Comparison of multiple spin echo and low flip angle gradient echo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Takamichi; Fujita, Norihiko; Harada, Koushi; Kozuka, Takahiro (Osaka Univ. (Japan). Faculty of Medicine)

    1989-07-01

    Sixteen patients including 13 cases with disk herniation and 3 cases with spondylosis of lumbar spine were examined on a resistive MRI system operating at 0.1 T. All lesions were studied with both multiple spin echo (MSE) and low flip angle gradient echo (LF) techniques to evaluate which technique is more effective in detecting the disk degeneration and the indentation on subarachnoid space. MSE images were obtained with repetition time (TR) of 1100-1500 ms or cardiac gating, an echo time (TE) of 30, 60, 90, 120, 150, and 180 ms symmetrical 6 echoes, and total acquisition time of more than 281 sec. LF images were obtained with TR of 500, 250, and 100 ms, TE of 18 ms, a flip angle of 30 degree, and total acquisition time of 128 sec. Eleven lesions of spinal disk degeneration and 12 of indentation on subarachnoid space were detected with LF. On the other hand, 26 lesions of spinal disk degeneration and 38 of indentation on subarachnoid space were detected with MSE. Although the parameters of LF employed in this study were relatively effective to emphasize T2{sup *}-based contrast, the ability of LF in detection of spinal disk degeneration and indentation on subarachnoid space is less than that of MSE. Signal contrast to noise ratios for normal disk and degenerative disk, epidural-fat and disk herniated material, CSF and disk herniated material, and epidural-fat and CSF were less than 4 with LF, but more than 4 with MSE. This difference of contrast to noise ratio between MSE and LF was one of the main causes of the difference of the detection rate of spinal disk degeneration and indentation on subarachnoid space. (author).

  18. Diuretic-enhanced gadolinium excretory MR urography: comparison of conventional gradient-echo sequences and echo-planar imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nolte-Ernsting, C.C.A.; Tacke, J.; Adam, G.B.; Haage, P.; Guenther, R.W. [Univ. of Technology, Aachen (Germany). Dept. of Diagnostic Radiology; Jung, P.; Jakse, G. [Univ. of Technology, Aachen (Germany). Dept. of Urology

    2001-01-01

    The aim of this study was to investigate the utility of different gadolinium-enhanced T1-weighted gradient-echo techniques in excretory MR urography. In 74 urologic patients, excretory MR urography was performed using various T1-weighted gradient-echo (GRE) sequences after injection of gadolinium-DTPA and low-dose furosemide. The examinations included conventional GRE sequences and echo-planar imaging (GRE EPI), both obtained with 3D data sets and 2D projection images. Breath-hold acquisition was used primarily. In 20 of 74 examinations, we compared breath-hold imaging with respiratory gating. Breath-hold imaging was significantly superior to respiratory gating for the visualization of pelvicaliceal systems, but not for the ureters. Complete MR urograms were obtained within 14-20 s using 3D GRE EPI sequences and in 20-30 s with conventional 3D GRE sequences. Ghost artefacts caused by ureteral peristalsis often occurred with conventional 3D GRE imaging and were almost completely suppressed in EPI sequences (p < 0.0001). Susceptibility effects were more pronounced on GRE EPI MR urograms and calculi measured 0.8-21.7% greater in diameter compared with conventional GRE sequences. Increased spatial resolution degraded the image quality only in GRE-EPI urograms. (orig.)

  19. What a plant sounds like: the statistics of vegetation echoes as received by echolocating bats.

    Directory of Open Access Journals (Sweden)

    Yossi Yovel

    2009-07-01

    Full Text Available A critical step on the way to understanding a sensory system is the analysis of the input it receives. In this work we examine the statistics of natural complex echoes, focusing on vegetation echoes. Vegetation echoes constitute a major part of the sensory world of more than 800 species of echolocating bats and play an important role in several of their daily tasks. Our statistical analysis is based on a large collection of plant echoes acquired by a biomimetic sonar system. We explore the relation between the physical world (the structure of the plant and the characteristics of its echo. Finally, we complete the story by analyzing the effect of the sensory processing of both the echolocation and the auditory systems on the echoes and interpret them in the light of information maximization. The echoes of all different plant species we examined share a surprisingly robust pattern that was also reproduced by a simple Poisson model of the spatial reflector arrangement. The fine differences observed between the echoes of different plant species can be explained by the spatial characteristics of the plants. The bat's emitted signal enhances the most informative spatial frequency range where the species-specific information is large. The auditory system filtering affects the echoes in a similar way, thus enhancing the most informative spatial frequency range even more. These findings suggest how the bat's sensory system could have evolved to deal with complex natural echoes.

  20. Compressed Sensing for fMRI: Feasibility Study on the Acceleration of Non-EPI fMRI at 9.4T

    Directory of Open Access Journals (Sweden)

    Paul Kyu Han

    2015-01-01

    Full Text Available Conventional functional magnetic resonance imaging (fMRI technique known as gradient-recalled echo (GRE echo-planar imaging (EPI is sensitive to image distortion and degradation caused by local magnetic field inhomogeneity at high magnetic fields. Non-EPI sequences such as spoiled gradient echo and balanced steady-state free precession (bSSFP have been proposed as an alternative high-resolution fMRI technique; however, the temporal resolution of these sequences is lower than the typically used GRE-EPI fMRI. One potential approach to improve the temporal resolution is to use compressed sensing (CS. In this study, we tested the feasibility of k-t FOCUSS—one of the high performance CS algorithms for dynamic MRI—for non-EPI fMRI at 9.4T using the model of rat somatosensory stimulation. To optimize the performance of CS reconstruction, different sampling patterns and k-t FOCUSS variations were investigated. Experimental results show that an optimized k-t FOCUSS algorithm with acceleration by a factor of 4 works well for non-EPI fMRI at high field under various statistical criteria, which confirms that a combination of CS and a non-EPI sequence may be a good solution for high-resolution fMRI at high fields.

  1. Evaluation of the spoilage potential of bacteria isolated from spoiled cooked whole tropical shrimp (Penaeus vannamei) stored under modified atmosphere packaging

    OpenAIRE

    Mace, Sabrina; Cardinal, Mireille; Jaffres, Emmanuel; Cornet, Josiane; Lalanne, Valerie; Chevalier, Frederique; Serot, Thierry; Pilet, Marie-france; Dousset, Xavier; Joffraud, Jean-jacques

    2014-01-01

    The spoilage potential of isolates belonging to five bacterial groups/species (Shewanella baltica, Carnobacterium maltaromaticum, Aeromonas salmonicida, Vibrio sp., “other Gamma-Proteobacteria” [containing one strain of Pseudoalteromonas sp. and one strain of Psychrobacter sp.]) isolated from spoiled cooked and whole tropical shrimp stored under modified atmosphere packaging (MAP) was evaluated by inoculation into ionized cooked and peeled tropical shrimp followed by storage for 32 days at 8°...

  2. Intraluminal filling defects of the bile ducts: differentiation of stones from tumors-the value of magnetic resonance cholangiography in conjunction with a 3D spoiled gradient echo gadolinium enhanced dynamic sequence

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soo Jin; Kim, Suk; Kim, Chang Won [Busan National University Hospital, Busan (Korea, Republic of)] (and others)

    2006-05-15

    We wanted to determinate the value of a dynamic volumetric interpolated breath-hold examination (VIBE) as a supplement to MR cholangiography for differentiating biliary stones from tumors when patient are suspected of having intraluminal filling defects on direct cholangiography. A retrospective analysis was performed for 49 patients who underwent MRI among all the patients who showed intraluminal filling defects on direct cholangiography for evaluating the cause of their jaundice from June 2002 to June 2003. After dividing these patients into two groups; i.e., the group with stones and the group wth tumors, we analyzed and compared each MR patterns of 1) signal intensity, 2) shape, and 3) enhancement. High signal intensity on T1-weighted images ({rho} < 0.001, X{sup 2} test), dark signal intensity on T2-weighted images ({rho} < 0.01, Fisher' s exact test) or smooth contour of intraluminal filling defects ({rho} < 0.001, X{sup 2} test) could be significantly suggestive findings of stone rather than a tumor mass. Dynamic VIBE is the most specific sequence for differentiating non-enhancing stone from an enhancing mass ({rho} < 0.001, Fisher' s exact test). We showed that MR cholangiography, when added to the dynamic VIBE sequences, could be an important imaging technique for patients who are suspected of having intraluminal filling defects on direct cholangiography to differentiate stones from tumors. Especially, the addition of dynamic VIBE images can provide the increased level of confidence in the diagnosis.

  3. The effect of blood inflow and B(1)-field inhomogeneity on measurement of the arterial input function in axial 3D spoiled gradient echo dynamic contrast-enhanced MRI.

    Science.gov (United States)

    Roberts, Caleb; Little, Ross; Watson, Yvonne; Zhao, Sha; Buckley, David L; Parker, Geoff J M

    2011-01-01

    A major potential confound in axial 3D dynamic contrast-enhanced magnetic resonance imaging studies is the blood inflow effect; therefore, the choice of slice location for arterial input function measurement within the imaging volume must be considered carefully. The objective of this study was to use computer simulations, flow phantom, and in vivo studies to describe and understand the effect of blood inflow on the measurement of the arterial input function. All experiments were done at 1.5 T using a typical 3D dynamic contrast-enhanced magnetic resonance imaging sequence, and arterial input functions were extracted for each slice in the imaging volume. We simulated a set of arterial input functions based on the same imaging parameters and accounted for blood inflow and radiofrequency field inhomogeneities. Measured arterial input functions along the vessel length from both in vivo and the flow phantom agreed with simulated arterial input functions and show large overestimations in the arterial input function in the first 30 mm of the vessel, whereas arterial input functions measured more centrally achieve accurate contrast agent concentrations. Use of inflow-affected arterial input functions in tracer kinetic modeling shows potential errors of up to 80% in tissue microvascular parameters. These errors emphasize the importance of careful placement of the arterial input function definition location to avoid the effects of blood inflow. © 2010 Wiley-Liss, Inc.

  4. Nomograms to calculate stability in slate and granite spoil heaps; Abacos para el calculo de estabilidad en escombreras de pizarra y granito

    Energy Technology Data Exchange (ETDEWEB)

    Paz Freire, M.; Taboada Castro, J.; Rivas Brea, T.; Giraldez Perez, E.; Araujo Fernandez, M.

    2011-07-01

    One of the main problems involved in the mining of slate and ornamental granite is the unavoidable generation of waste rock, which must be stored in spoil heaps under suitably integrated, secure and stable conditions. Our work here focuses on this last point. To study the risk of instability within spoil heaps we have analysed the performance of a wide number of models with regard to circular slope failure, taking into account the different degrees of compactness of the material, the characteristics of the material itself, the effect of water pressure and the geometry of the heap. From this analysis we obtained more than 300 safety criteria, which were then used to draw up a series of nomograms to allow us to determine the risk of sliding in any granite or slate spoil heap. Thus, nomograms prove themselves to be suitable, quick, easy-to-use tools for preliminary studies of new structures, for periodic analyses of existing structures and to investigate structures that are due to be modified. (Author) 24 refs.

  5. Integration of thermal digital 3D model and a MASW (Multichannel Analysis of Surface Wave as a means of improving monitoring of spoil tip stability

    Directory of Open Access Journals (Sweden)

    Lewińska Paulina

    2018-01-01

    Full Text Available Spoil tips are anthropogenic terrain structures built of leftover (coal mining materials. They consist mostly of slate and sandstone or mudstone but also include coal and highly explosive coal dust. Coal soil tip fires cause an irreversible degradation to the environment. Government organizations notice the potential problem of spoil tip hazard and are looking for ways of fast monitoring of their temperature and inside structure. In order to test new monitoring methods an experimental was performed in the area of spoil tip of Lubelski Węgiel „Bogdanka” S.A. A survey consisted of creating a 3D discreet thermal model. This was done in order to look for potential fire areas. MASW (Multichannel analysis of surface wave was done in order to find potential voids within the body of a tip. Existing data was digitalized and a 3D model of object’s outside and inside was produced. This article provides results of this survey and informs about advantages of such an approach.

  6. Integration of thermal digital 3D model and a MASW (Multichannel Analysis of Surface Wave) as a means of improving monitoring of spoil tip stability

    Science.gov (United States)

    Lewińska, Paulina; Matuła, Rafał; Dyczko, Artur

    2018-01-01

    Spoil tips are anthropogenic terrain structures built of leftover (coal) mining materials. They consist mostly of slate and sandstone or mudstone but also include coal and highly explosive coal dust. Coal soil tip fires cause an irreversible degradation to the environment. Government organizations notice the potential problem of spoil tip hazard and are looking for ways of fast monitoring of their temperature and inside structure. In order to test new monitoring methods an experimental was performed in the area of spoil tip of Lubelski Węgiel "Bogdanka" S.A. A survey consisted of creating a 3D discreet thermal model. This was done in order to look for potential fire areas. MASW (Multichannel analysis of surface wave) was done in order to find potential voids within the body of a tip. Existing data was digitalized and a 3D model of object's outside and inside was produced. This article provides results of this survey and informs about advantages of such an approach.

  7. Research on adaptive acoustic echo cancellation algorithm in digital hearing aids

    Science.gov (United States)

    Ma, Min; Wang, Mingjiang; Hu, Jiebin

    2017-08-01

    At present, the study of acoustic echo cancellation (AEC) is mainly based on the adaptive acoustic echo cancellation algorithm. It is proved that the echo signal of the near-end microphone must be compensated by the time delay to achieve the purpose of echo cancellation, and the accuracy of the delay estimation affecting the final effect of echo cancellation. This paper proposes a combination of the normalized minimum mean square algorithm (NLMS) and the time delay estimation model to solve the echo problem in hearing aids. In this paper, using generalized cross correlation (GCC) to estimate time delay. In addition, using the energy, Teager-Kaiser Energy Operator (TKEO) and the signal correlation coefficient as the threshold value to detect the howling signal in digital hearing aids. Finally, the simulation and experimental results are given. The experiment proves that the method has good effect.

  8. Plant Communities Rather than Soil Properties Structure Arbuscular Mycorrhizal Fungal Communities along Primary Succession on a Mine Spoil

    Directory of Open Access Journals (Sweden)

    Petr Kohout

    2017-04-01

    Full Text Available Arbuscular mycorrhizal fungal (AMF community assembly during primary succession has so far received little attention. It remains therefore unclear, which of the factors, driving AMF community composition, are important during ecosystem development. We addressed this question on a large spoil heap, which provides a mosaic of sites in different successional stages under different managements. We selected 24 sites of c. 12, 20, 30, or 50 years in age, including sites with spontaneously developing vegetation and sites reclaimed by alder plantations. On each site, we sampled twice a year roots of the perennial rhizomatous grass Calamagrostis epigejos (Poaceae to determine AMF root colonization and diversity (using 454-sequencing, determined the soil chemical properties and composition of plant communities. AMF taxa richness was unaffected by site age, but AMF composition variation increased along the chronosequences. AMF communities were unaffected by soil chemistry, but related to the composition of neighboring plant communities of the sampled C. epigejos plants. In contrast, the plant communities of the sites were more distinctively structured than the AMF communities along the four successional stages. We conclude that AMF and plant community successions respond to different factors. AMF communities seem to be influenced by biotic rather than by abiotic factors and to diverge with successional age.

  9. Aluminum-Tolerant Pisolithus Ectomycorrhizas Confer Increased Growth, Mineral Nutrition, and Metal Tolerance to Eucalyptus in Acidic Mine Spoil

    Directory of Open Access Journals (Sweden)

    Louise Egerton-Warburton

    2015-01-01

    Full Text Available Ectomycorrhizal fungi (ECM may increase the tolerance of their host plants to Al toxicity by immobilizing Al in fungal tissues and/or improving plant mineral nutrition. Although these benefits have been demonstrated in in vitro (pure culture or short-term nutrient solution (hydroponic experiments, fewer studies have examined these benefits in the field. This study examined the growth, mineral nutrition, and Al levels in two Eucalyptus species inoculated with three Pisolithus ecotypes that varied in Al tolerance (in vitro and grown in mine spoil in the greenhouse and field. All three ecotypes of Pisolithus improved Eucalyptus growth and increased host plant tolerance to Al in comparison to noninoculated plants. However, large variations in plant growth and mineral nutrition were detected among the Pisolithus-inoculated plants; these differences were largely explained by the functional properties of the Pisolithus inoculum. Seedlings inoculated with the most Al-tolerant Pisolithus inoculum showed significantly higher levels of N, P, Ca, Mg, and K and lower levels of Al than seedlings inoculated with Al-sensitive ecotypes of Pisolithus. These findings indicate an agreement between the fungal tolerance to Al in vitro and performance in symbiosis, indicating that both ECM-mediated mineral nutrient acquisition and Al accumulation are important in increasing the host plant Al tolerance.

  10. CCR7 expressing mesenchymal stem cells potently inhibit graft-versus-host disease by spoiling the fourth supplemental Billingham's tenet.

    Directory of Open Access Journals (Sweden)

    Hong Li

    Full Text Available The clinical acute graft-versus-host disease (GvHD-therapy of mesenchymal stem cells (MSCs is not as satisfactory as expected. Secondary lymphoid organs (SLOs are the major niches serve to initiate immune responses or induce tolerance. Our previous study showed that CCR7 guide murine MSC line C3H10T1/2 migrating to SLOs. In this study, CCR7 gene was engineered into murine MSCs by lentivirus transfection system (MSCs/CCR7. The immunomodulatory mechanism of MSCs/CCR7 was further investigated. Provoked by inflammatory cytokines, MSCs/CCR7 increased the secretion of nitric oxide and calmed down the T cell immune response in vitro. Immunofluorescent staining results showed that transfused MSCs/CCR7 can migrate to and relocate at the appropriate T cell-rich zones within SLOs in vivo. MSCs/CCR7 displayed enhanced effect in prolonging the survival and alleviating the clinical scores of the GvHD mice than normal MSCs. Owing to the critical relocation sites, MSCs/CCR7 co-infusion potently made the T cells in SLOs more naïve like, thus control T cells trafficking from SLOs to the target organs. Through spoiling the fourth supplemental Billingham's tenet, MSCs/CCR7 potently inhibited the development of GvHD. The study here provides a novel therapeutic strategy of MSCs/CCR7 infusion at a low dosage to give potent immunomodulatory effect for clinical immune disease therapy.

  11. Richness, diversity and evenness of vegetation upon rehabilitation of gypsum mine spoiled lands in the Indian arid zone

    Science.gov (United States)

    Kumar, S.; Sharma, K.D.; Sharma, U.K.; Gough, L.P.

    1998-01-01

    Richness, diversity and evenness of vegetation, after rehabilitation of gypsum mine spoils at Barmer were investigated in plots protected and planted one year and four years ago. There were four water harvesting treatments, viz., half-moon terraces, micro-catchments with 5% slope, ridge and furrow and control, wherein, indigenous and exotic trees and shrubs were planted at 5 ?? 5 m spacing. Sampling of the planted and natural vegetation, using quadrats and transacts, revealed much less species richness in unplanted control as compared to all treatments and in all the years. The species richness that increased initially (within one year) gradually declined over time (during four year), though the extent varied in different treatments. The water harvesting treatment showing maximum initial increase in richness also showed maximum decline over time, though decline was more in annual species. Two perennial species increased in richness with time. This was further proved from the trends in diversity and evenness indices. It was concluded that natural successional process was accelerated by rehabilitation providing stability to the habitat.

  12. Cross Spectral Analysis of CODAR-SeaSonde Echoes from Sea Surface and Ionosphere at Taiwan

    Directory of Open Access Journals (Sweden)

    Chien-Ya Wang

    2017-01-01

    Full Text Available It is well known that the primary targets responsible for first-order sea echoes observed by a High-Frequency (HF radar are the advancing and receding ocean waves with the wavelengths at Bragg scales. However, in light of the fact that the ionospheric sporadic E (Es and F layers may be present in the viewing range of the HF radar for ocean wave detection, the radar returns reflected from the F and Es layers may significantly contaminate the ocean wave power spectrum. The characteristics of the first-order sea echoes and ionospheric interferences measured by the CODAR-SeaSonde in Taiwan area are analyzed and presented in this article. The coherences and phases of the normalized cross spectra of the sea and ionospheric echoes between different pairs of the receiving channels are calculated, respectively. One of the striking features presented in this report is that the ionospheric echo heights scaled from the ionogram observed by the Chung-Li ionosonde are about 30 km lower than those observed by the DATAN CODAR-SeaSonde. It is also found that the coherences of the sea echoes are generally smaller than those of the ionospheric echoes by about 15% on average, and the phase fluctuations (standard deviations of the sea echoes are substantially larger than those of the ionospheric layer reflection echoes. In addition, statistics show that the sum of the mean phases of the ionospheric echoes between the three receiving channel pairs is approximately zero, while it is not for the sea echoes. These results seem to suggest that the use of the discrepancies in the characteristics of the coherences and phases between the sea and ionospheric echoes may provide a potential means to be helpful to distinguish the sea and ionospheric echoes in the CODAR-SeaSonde observed cross power spectrum.

  13. Seafloor classification using acoustic backscatter echo-waveform - Artificial neural network applications

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Mahale, V.; Navelkar, G.S.; Desai, R.G.P.

    Seafloor classification using echo-waveform data acquired through echo-sounding systems is well known method [1]. Understanding of the seafloor characteristics is important, however, requires suitable classifications technique. In general, seafloor..., scattering of sound signal is generally controlled by these factors, and multi-parameter scattering models based seafloor classification using echo waveform data were attempted. However, such model based techniques are data independent and may not allow...

  14. Crack depth measurement by flaw tip echo method

    International Nuclear Information System (INIS)

    Yoneyama, H.; Shibata, S.; Kishihami, M.; Takama, S.; Kazuoka, S.

    1985-01-01

    The depth of crack generated in the heat-affected zone of weldments in austenitic stainless steel piping by intergranular stress corrosion cracking is measured by flaw tip echo method. Cracks generated by intergranular stress corrosion generally possess complex configuration, and are moreover closed and devoid of gap, which render them difficult to measure by ultrasonic technique, but experiment with the proposed method proved the estimated crack depth to agree well with direct measurements made after the ultrasonic inspection by sectioning the crack, etching and observation by microscope. This new ultrasonic technique can thus be considered effective for estimating the depth of cracks produced by intergranular stress corrosion

  15. The echo-enabled harmonic generation options for FLASH II

    International Nuclear Information System (INIS)

    Deng, Haixiao; Decking, Winfried; Faatz, Bart

    2011-03-01

    FLASH II is an upgrade to the existing free electron laser (FEL) FLASH. The echo-enabled harmonic generation (EEHG) scheme is proposed to be a potential seeding option of FLASH II. In this paper, the possibility of EEHG operation of FLASH II is investigated for the first time. With a combination of existing numerical codes, i.e. a laser-beam interaction code in an undulator (LBICU), a beam tracking code in a chicane (ELEGANT) and an universal FEL simulating code (GENESIS), the effects of beam energy chirp and coherent synchrotron radiation (CSR) on EEHG operation are studied as well. In addition, several interesting issues concerning EEHG simulation are discussed. (orig.)

  16. Identification of pulse echo impulse responses for multi source transmission

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jensen, Jørgen Arendt

    2004-01-01

    is a mixture of the information corresponding to several transmitters. There is, thus, no direct way of determining which information corresponds to which transmitter, preventing proper focusing. In this paper we decode the received signal by estimating the pulse echo impulse responses between every....... The method is evaluated using the simulation tool Field II. Three point spread functions are simulated where axial movement of 1 m/s is present. The axial resolution for the moving scatterer is 0.249 mm (-3dB) and 0.291 mm (-6dB), which is compared to a standard STA transmission scheme with sequential...

  17. CFAR Detection from Noncoherent Radar Echoes Using Bayesian Theory

    Directory of Open Access Journals (Sweden)

    Wataru Suganuma

    2010-01-01

    Full Text Available We propose a new constant false alarm rate (CFAR detection method from noncoherent radar echoes, considering heterogeneous sea clutter. It applies the Bayesian theory for adaptive estimation of the local clutter statistical distribution in the cell under test. The detection technique can be readily implemented in existing noncoherent marine radar systems, which makes it particularly attractive for economical CFAR detection systems. Monte Carlo simulations were used to investigate the detection performance and demonstrated that the proposed technique provides a higher probability of detection than conventional techniques, such as cell averaging CFAR (CA-CFAR, especially with a small number of reference cells.

  18. CFAR Detection from Noncoherent Radar Echoes Using Bayesian Theory

    Directory of Open Access Journals (Sweden)

    Yamaguchi Hiroyuki

    2010-01-01

    Full Text Available Abstract We propose a new constant false alarm rate (CFAR detection method from noncoherent radar echoes, considering heterogeneous sea clutter. It applies the Bayesian theory for adaptive estimation of the local clutter statistical distribution in the cell under test. The detection technique can be readily implemented in existing noncoherent marine radar systems, which makes it particularly attractive for economical CFAR detection systems. Monte Carlo simulations were used to investigate the detection performance and demonstrated that the proposed technique provides a higher probability of detection than conventional techniques, such as cell averaging CFAR (CA-CFAR, especially with a small number of reference cells.

  19. Extraction of scattering echo time by surf noise background subtracted autocorrelation.

    Science.gov (United States)

    Li, Xiaolei; Chi, Jing; Gao, Dazhi; Li, Jie; Wang, Ning

    2017-07-01

    Extracting echo time is an important step in scatterer detection by ambient noise, while in general the scattered signal is weak and submerged in the background. An experiment of a Polyvinyl chloride pipe in a coastline surf noise environment is designed to extract the pipe's echo time by noise autocorrelation. As expected, the scattered wave of the pipe is submerged in an autocorrelation signal. A method called background subtracted autocorrelation is proposed in this paper, which can retrieve scattered echo time from autocorrelation signal effectively. And the biggest relative error of extracted echo time is less than 2% in the experiment.

  20. Efficient Fast Stereo Acoustic Echo Cancellation Based on Pairwise Optimal Weight Realization Technique

    Directory of Open Access Journals (Sweden)

    Yukawa Masahiro

    2006-01-01

    Full Text Available In stereophonic acoustic echo cancellation (SAEC problem, fast and accurate tracking of echo path is strongly required for stable echo cancellation. In this paper, we propose a class of efficient fast SAEC schemes with linear computational complexity (with respect to filter length. The proposed schemes are based on pairwise optimal weight realization (POWER technique, thus realizing a "best" strategy (in the sense of pairwise and worst-case optimization to use multiple-state information obtained by preprocessing. Numerical examples demonstrate that the proposed schemes significantly improve the convergence behavior compared with conventional methods in terms of system mismatch as well as echo return loss enhancement (ERLE.

  1. Examining the robustness of automated aural classification of active sonar echoes.

    Science.gov (United States)

    Murphy, Stefan M; Hines, Paul C

    2014-02-01

    Active sonar systems are used to detect underwater man-made objects of interest (targets) that are too quiet to be reliably detected with passive sonar. Performance of active sonar can be degraded by false alarms caused by echoes returned from geological seabed structures (clutter) in shallow regions. To reduce false alarms, a method of distinguishing target echoes from clutter echoes is required. Research has demonstrated that perceptual-based signal features similar to those employed in the human auditory system can be used to automatically discriminate between target and clutter echoes, thereby reducing the number of false alarms and improving sonar performance. An active sonar experiment on the Malta Plateau in the Mediterranean Sea was conducted during the Clutter07 sea trial and repeated during the Clutter09 sea trial. The dataset consists of more than 95,000 pulse-compressed echoes returned from two targets and many geological clutter objects. These echoes were processed using an automatic classifier that quantifies the timbre of each echo using a number of perceptual signal features. Using echoes from 2007, the aural classifier was trained to establish a boundary between targets and clutter in the feature space. Temporal robustness was then investigated by testing the classifier on echoes from the 2009 experiment.

  2. Finland HF and Esrange MST radar observations of polar mesosphere summer echoes

    Directory of Open Access Journals (Sweden)

    T. Ogawa

    2003-04-01

    Full Text Available Peculiar near range echoes observed in summer with the SuperDARN HF radar in Finland are presented. The echoes were detected at four frequencies of 9, 11, 13 and 15 MHz at slant ranges of 105–250 km for about 100 min. Interferometer measurements indicate that the echoes are returned from 80–100 km altitudes with elevation angles of 20°–60°. Echo power (< 16 dB, Doppler velocity (between –30 and + 30 ms-1 and spectral width (< 60 ms-1 fluctuate with periods of several to 20 min, perhaps due to short–period atmospheric gravity waves. When the HF radar detected the echoes, a vertical incidence MST radar, located at Esrange in Sweden (650 km north of the HF radar site, observed polar mesosphere summer echoes (PMSE at altitudes of 80–90 km. This fact suggests that the near range HF echoes are PMSE at HF band, although both radars did not probe a common volume. With increasing radar frequency, HF echo ranges are closer to the radar site and echo power becomes weaker. Possible mechanisms to explain these features are discussed.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides; instruments and techniques

  3. Finland HF and Esrange MST radar observations of polar mesosphere summer echoes

    Directory of Open Access Journals (Sweden)

    T. Ogawa

    Full Text Available Peculiar near range echoes observed in summer with the SuperDARN HF radar in Finland are presented. The echoes were detected at four frequencies of 9, 11, 13 and 15 MHz at slant ranges of 105–250 km for about 100 min. Interferometer measurements indicate that the echoes are returned from 80–100 km altitudes with elevation angles of 20°–60°. Echo power (< 16 dB, Doppler velocity (between –30 and + 30 ms-1 and spectral width (< 60 ms-1 fluctuate with periods of several to 20 min, perhaps due to short–period atmospheric gravity waves. When the HF radar detected the echoes, a vertical incidence MST radar, located at Esrange in Sweden (650 km north of the HF radar site, observed polar mesosphere summer echoes (PMSE at altitudes of 80–90 km. This fact suggests that the near range HF echoes are PMSE at HF band, although both radars did not probe a common volume. With increasing radar frequency, HF echo ranges are closer to the radar site and echo power becomes weaker. Possible mechanisms to explain these features are discussed.

    Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; thermospheric dynamics; waves and tides; instruments and techniques

  4. Echo scintillation Index affected by cat-eye target's caliber with Cassegrain lens

    Science.gov (United States)

    Shan, Cong-miao; Sun, Hua-yan; Zhao, Yan-zhong; Zheng, Yong-hui

    2015-10-01

    The optical aperture of cat-eye target has the aperture averaging effect to the active detecting laser of active laser detection system, which can be used to identify optical targets. The echo scintillation characteristics of the transmission-type lens target have been studied in previous work. Discussing the differences of the echo scintillation characteristics between the transmission-type lens target and Cassegrain lens target can be helpful to targets classified. In this paper, the echo scintillation characteristics of Cat-eye target's caliber with Cassegrain lens has been discussed . By using the flashing theory of spherical wave in the weak atmospheric turbulence, the annular aperture filter function and the Kolmogorov power spectrum, the analytic expression of the scintillation index of the cat-eye target echo of the horizontal path two-way transmission was given when the light is normal incidence. Then the impact of turbulence inner and outer scale to the echo scintillation index and the analytic expression of the echo scintillation index at the receiving aperture were presented using the modified Hill spectrum and the modified Von Karman spectrum. Echo scintillation index shows the tendency of decreasing with the target aperture increases and different ratios of the inner and outer aperture diameter show the different echo scintillation index curves. This conclusion has a certain significance for target recognition in the active laser detection system that can largely determine the target type by largely determining the scope of the cat-eye target which depending on echo scintillation index.

  5. Meniscal tears: comparison of the conventional spin-echo and fast spin-echo techniques through image processing.

    Science.gov (United States)

    Nogueira, Ibevan A; Frère, Annie F; Silva, Alessandro P; de Oliveira, Heverton C

    2014-03-27

    Conventional spin-echo (PD-CSE) and fast spin-echo (PD-FSE) techniques are frequently used to detect meniscal tears. However, the time delay for imaging with PD-CSE has resulted in its replacement with faster techniques, such as proton density fast spin-echo (PD-FSE), which has become a frequent tool at most diagnostic centres.Qualitative analysis shows that the PD-CSE technique is more sensitive, but other authors have not found significant differences between the aforementioned techniques. Therefore, we performed a quantitative analysis in this study that aims to measure differences in the quality of the images obtained with both techniques. We compared the PD-CSE and PD-FSE techniques by quantitatively analysing the obtained proton density images: the area shown, as well as the brightness and lesion contrast of the obtained image.A set of 100 images from 50 patients thought to contain meniscal tears of the knee were selected. These 100 images were obtained from all individuals using both the PD-CSE and PD-FSE techniques. The images were processed using software developed in Delphi. In addition to these quantifications, three physicians, who are specialists in radiology and capable of analysing magnetic resonance (MR) images of the musculoskeletal system, qualitatively analysed the diagnostic sensitivity of both techniques. On average, samples obtained via the PD-CSE technique contained 22% more pixels in the lesion area. The contrast differed by 28%, and the brightness differed by 31%. The two techniques were correlated using Student's t-test, which showed a statistically significant difference. The specialists detected meniscal tears in 30 of the images obtained via the PD-CSE technique, while only 72% of these cases were detected via the PD-FSE technique. The PD-CSE technique was shown to be superior to PD-FSE for all of the evaluated properties, making its selection preferable.

  6. ESA M3 mission candidate EChO

    Science.gov (United States)

    Puig, L.; Isaak, K. G.; Escudero, I.; Martin, D.; Crouzet, P.-E.; Rando, N.

    2011-09-01

    The Exoplanet Characterisation Observatory (EChO) is a medium class mission candidate within the science program Cosmic Vision 2015-2025 of the European Space Agency. It was selected in February 2011 as one of 4 M3 mission candidates to enter an assessment phase. The assessment activities start with the definition of science and mission requirements as well as of a preliminary model payload, followed by an internal Concurrent Design Facility (CDF) study. Parallel industrial studies will follow in 2012, after which the 4 missions will be reviewed to identify candidates entering definition phase studies in 2013. EChO aims at characterising the atmosphere of known transiting exoplanets, potentially from giant Hot Jupiters down to Super-Earths orbiting in the habitable zone of M-dwarf stars. It will use a 1 m class telescope, feeding a spectrometer covering the wave lengths from 0.4 to 11 microns with a potential extension to 16 microns. While spatial differentiation of the exoplanet and its host star is not necessary, spectral differentiation will be achieved by making differential measurements of in- and out- of transit frames to cancel the star signal. This paper describes critical requirements, and gives an overview of the model payload design. It also reports on the results of the CDF.

  7. Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV)

    Science.gov (United States)

    Falahatpisheh, Ahmad; Kheradvar, Arash

    2015-11-01

    Measurement of 3D flow field inside the cardiac chambers has proven to be a challenging task. Current laser-based 3D PIV methods estimate the third component of the velocity rather than directly measuring it and also cannot be used to image the opaque heart chambers. Modern echocardiography systems are equipped with 3D probes that enable imaging the entire 3D opaque field. However, this feature has not yet been employed for 3D vector characterization of blood flow. For the first time, we introduce a method that generates velocity vector field in 4D based on volumetric echocardiographic images. By assuming the conservation of brightness in 3D, blood speckles are tracked. A hierarchical 3D PIV method is used to account for large particle displacement. The discretized brightness transport equation is solved in a least square sense in interrogation windows of size 163 voxels. We successfully validate the method in analytical and experimental cases. Volumetric echo data of a left ventricle is then processed in the systolic phase. The expected velocity fields were successfully predicted by V-Echo-PIV. In this work, we showed a method to image blood flow in 3D based on volumetric images of human heart using no contrast agent.

  8. Chirp echo Fourier transform EPR-detected NMR

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies.

  9. Radar cross sections for mesospheric echoes at Jicamarca

    Directory of Open Access Journals (Sweden)

    G. A. Lehmacher

    2009-07-01

    Full Text Available Radar cross sections (RCS of mesospheric layers at 50 MHz observed at Jicamarca, Peru, range from 10−18 to 10−16 m−1, three orders of magnitudes smaller than cross sections reported for polar mesospheric winter echoes during solar proton events and six orders of magnitude smaller than polar mesospheric summer echoes. Large RCS are found in thick layers around 70 km that also show wide radar spectra, which is interpreted as turbulent broadening. For typical atmospheric and ionospheric conditions, volume scattering RCS for stationary, homogeneous, isotropic turbulence at 3 m are also in the range 10−18 to 10−16 m−1, in reasonable agreement with measurements. Moreover, theory predicts maximum cross sections around 70 km, also in agreement with observations. Theoretical values are still a matter of order-of-magnitude estimation, since the Bragg scale of 3 m is near or inside the viscous subrange, where the form of the turbulence spectrum is not well known. In addition, steep electron density gradients can increase cross-sections significantly. For thin layers with large RCS and narrow spectra, isotropic turbulence theory fails and scattering or reflection from anisotropic irregularities may gain relevance.

  10. First observations of polar mesosphere summer echoes in Antarctica

    Science.gov (United States)

    Woodman, Ronald F.; Balsley, Ben B.; Aquino, Fredy; Flores, Luis; Vazquez, Edilberto; Sarango, Martin; Huaman, Mercedes M.; Soldi, Hector

    1999-10-01

    A 25-kW peak power 50-MHz radar was installed at the Peruvian base on King George Island, Antarctica (62°S), in early 1993. A search for polar mesospheric summer echoes (PMSEs) was made during late January and early February of the first year of operation with negative results. These results have been reported in the literature [Balsley et al., 1993; 1995]. We report here results obtained during the austral summer of the second year (1994) of operation. Observations during the second year were begun earlier, i.e., closer to the austral summer solstice. PMSEs were observed during this period, albeit the echoes were much weaker than what one would expect based on earlier Poker Flat radar results at a comparable latitude (65°N) in the Northern Hemisphere. A large and measurable asymmetry in PMSE strength in the two hemispheres therefore exists. We explain this asymmetry by postulating a difference in summer mesopause temperatures between the two hemispheres of ~7.5 K. This difference has been estimated using an empirical relationship between the variations of the Poker Flat PMSE power as a function of temperature given by the mass spectrometer incoherent scatter extended (MSISE-90) model.

  11. MR respiratory navigator echo gated coronary angiography at 3 T

    International Nuclear Information System (INIS)

    Chang Shixin; Wang Yibin; Zong Genlin; Hao Nanxin; Du Yushan

    2007-01-01

    Objective: To investigate the techniques and influence factors for the respiratory navigator echo triggered whole-heart coronary MR angiography (WH-CMRA) and evaluate its application in visualizing coronary arteries and the image quality. Methods: Ninety two volunteers were acquired with WH-CMRA at 3 T MR scanner using respiratory navigator-echo gated TFE sequence. Imaging quality was visually graded as 0-IV grade according to the visual inspection, average length, diameter and sharpness of coronary arteries. The correlation between the imaging quality and respiratory pattern, heart rate and navigator efficiency was analyzed. Results: The imaging quality in 92 cases was that 28 were graded as IV, 53 were graded as III, 9 were graded as II and 2 were graded as I. The successful rate of scan was 88% (81/92). The imaging quality is mainly graded as IV when the heart rate was less than 75 beats per minute (bpm) and the sharpness of vessel was (48±11)%. When heart rate was more than 75 bpm, the image quality was mostly graded as 111 and the sharpness was (33±15)%. The correlation between heart rate and imaging quality score was negative (r= -0.726, P O.05). Conclusion: 3 T WH-CMRA technique could facilitated the visualization of whole coronary arteries at free breathing but having indications on heart rate. (authors)

  12. EChO fine guidance sensor design and architecture

    Science.gov (United States)

    Ottensamer, Roland; Rataj, Miroslaw; Schrader, Jan-Rutger; Ferstl, Roman; Güdel, Manuel; Kerschbaum, Franz; Luntzer, Armin

    2014-08-01

    EChO, the Exoplanet Characterization Observatory, is an M-class candidate in the ESA Comic Vision programme. It will provide high resolution, multi-wavelength spectroscopic observations of exoplanets, measure their atmospheric composition, temperature and albedo. The scientific payload is a spectrometer covering the 0.4-11 micron waveband. High photometric stability over a time scale of about 10 hours is one of the most stringent requirements of the EChO mission. As a result, fine pointing stability relative to the host star is mandatory. This will be achieved through a Fine Guidance Sensor (FGS), a separate photometric channel that uses a fraction of the target star signal from the optical channel. The main task of the FGS is to ensure the centering, focusing and guiding of the satellite, but it will also provide supplemental high-precision astrometry and photometry of the target to ground for de-trending the spectra and complementary science. In this paper we give an overview of the current architectural design of the FGS subsystem and discuss related requirements as well as the expected performance.

  13. Echo Chambers: Emotional Contagion and Group Polarization on Facebook

    Science.gov (United States)

    Del Vicario, Michela; Vivaldo, Gianna; Bessi, Alessandro; Zollo, Fabiana; Scala, Antonio; Caldarelli, Guido; Quattrociocchi, Walter

    2016-12-01

    Recent findings showed that users on Facebook tend to select information that adhere to their system of beliefs and to form polarized groups - i.e., echo chambers. Such a tendency dominates information cascades and might affect public debates on social relevant issues. In this work we explore the structural evolution of communities of interest by accounting for users emotions and engagement. Focusing on the Facebook pages reporting on scientific and conspiracy content, we characterize the evolution of the size of the two communities by fitting daily resolution data with three growth models - i.e. the Gompertz model, the Logistic model, and the Log-logistic model. Although all the models appropriately describe the data structure, the Logistic one shows the best fit. Then, we explore the interplay between emotional state and engagement of users in the group dynamics. Our findings show that communities’ emotional behavior is affected by the users’ involvement inside the echo chamber. Indeed, to an higher involvement corresponds a more negative approach. Moreover, we observe that, on average, more active users show a faster shift towards the negativity than less active ones.

  14. The Bow Echo and MCV Experiment: Observations and Opportunities.

    Science.gov (United States)

    Davis, Christopher; Atkins, Nolan; Bartels, Diana; Bosart, Lance; Coniglio, Michael; Bryan, George; Cotton, William; Dowell, David; Jewett, Brian; Johns, Robert; Jorgensen, David; Knievel, Jason; Knupp, Kevin; Lee, Wen-Chau; McFarquhar, Gregory; Moore, James; Przybylinski, Ron; Rauber, Robert; Smull, Bradley; Trapp, Robert; Trier, Stanley; Wakimoto, Roger; Weisman, Morris; Ziegler, Conrad

    2004-08-01

    The Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) is a research investigation using highly mobile platforms to examine the life cycles of mesoscale convective systems. It represents a combination of two related investigations to study (a) bow echoes, principally those that produce damaging surface winds and last at least 4 h, and (b) larger convective systems that produce long-lived mesoscale convective vortices (MCVs). The field phase of BAMEX utilized three instrumented research aircraft and an array of mobile ground-based instruments. Two long-range turbo-prop aircraft were equipped with pseudodual-Doppler radar capability, the third aircraft was a jet equipped with dropsondes. The aircraft documented the environmental structure of mesoscale convective systems (MCSs), observed the kinematic and thermodynamic structure of the convective line and stratiform regions (where rear-inflow jets and MCVs reside), and captured the structure of mature MCVs. The ground-based instruments augmented sounding coverage and documented the thermodynamic structure of the PBL, both within MCSs and in their environment. The present article reviews the scientific goals of the study and the facility deployment strategy, summarizes the cases observed, and highlights the forthcoming significant research directions and opportunities.

  15. Investigating the Group-Level Impact of Advanced Dual-Echo fMRI Combinations

    Directory of Open Access Journals (Sweden)

    Adam Kettinger

    2016-12-01

    Full Text Available Multi-echo fMRI data acquisition has been widely investigated and suggested to optimize sensitivity for detecting the BOLD signal. Several methods have also been proposed for the combination of data with different echo times. The aim of the present study was to investigate how these advance echo combination methods provide advantages over the simple averaging of echoes when state-of-the-art group-level random-effect analyses are performed. Both resting-state and task-based dual-echo fMRI data were collected from 27 healthy adult individuals (14 male, mean age = 25.75 years using standard echo-planar acquisition methods at 3T. Both resting-state and task-based data were subjected to a standard image pre-processing pipeline. Subsequently the two echoes were combined as a weighted average, using four different strategies for calculating the weights: (1 simple arithmetic averaging, (2 BOLD sensitivity weighting, (3 temporal-signal-to-noise ratio weighting and (4 temporal BOLD sensitivity weighting. Our results clearly show that the simple averaging of data with the different echoes is sufficient. Advanced echo combination methods may provide advantages on a single-subject level but when considering random-effects group level statistics they provide no benefit regarding sensitivity (i.e. group-level t-values compared to the simple echo-averaging approach. One possible reason for the lack of clear advantages may be that apart from increasing the average BOLD sensitivity at the single-subject level, the advanced weighted averaging methods also inflate the inter-subject variance. As the echo combination methods provide very similar results, the recommendation is to choose between them depending on the availability of time for collecting additional resting-state data or whether subject-level or group-level analyses are planned.

  16. A Pilot Study Assessing ECG versus ECHO Ventriculoventricular Optimization in Pediatric Resynchronization Patients.

    Science.gov (United States)

    Punn, Rajesh; Hanisch, Debra; Motonaga, Kara S; Rosenthal, David N; Ceresnak, Scott R; Dubin, Anne M

    2016-02-01

    Cardiac resynchronization therapy indications and management are well described in adults. Echocardiography (ECHO) has been used to optimize mechanical synchrony in these patients; however, there are issues with reproducibility and time intensity. Pediatric patients add challenges, with diverse substrates and limited capacity for cooperation. Electrocardiographic (ECG) methods to assess electrical synchrony are expeditious but have not been extensively studied in children. We sought to compare ECHO and ECG CRT optimization in children. Prospective, pediatric, single-center cross-over trial comparing ECHO and ECG optimization with CRT. Patients were assigned to undergo either ECHO or ECG optimization, followed for 6 months, and crossed-over to the other assignment for another 6 months. ECHO pulsed-wave tissue Doppler and 12-lead ECG were obtained for 5 VV delays. ECG optimization was defined as the shortest QRSD and ECHO optimization as the lowest dyssynchrony index. ECHOs/ECGs were interpreted by readers blinded to optimization technique. After each 6 month period, these data were collected: ejection fraction, velocimetry-derived cardiac index, quality of life, ECHO-derived stroke distance, M-mode dyssynchrony, study cost, and time. Outcomes for each optimization method were compared. From June 2012 to December 2013, 19 patients enrolled. Mean age was 9.1 ± 4.3 years; 14 (74%) had structural heart disease. The mean time for optimization was shorter using ECG than ECHO (9 ± 1 min vs. 68 ± 13 min, P ECG. No other outcome differed between groups. ECHO optimization of synchrony was not superior to ECG optimization in this pilot study. ECG optimization required less time and cost than ECHO optimization. © 2015 Wiley Periodicals, Inc.

  17. Full-waveform LiDAR echo decomposition based on wavelet decomposition and particle swarm optimization

    Science.gov (United States)

    Li, Duan; Xu, Lijun; Li, Xiaolu

    2017-04-01

    To measure the distances and properties of the objects within a laser footprint, a decomposition method for full-waveform light detection and ranging (LiDAR) echoes is proposed. In this method, firstly, wavelet decomposition is used to filter the noise and estimate the noise level in a full-waveform echo. Secondly, peak and inflection points of the filtered full-waveform echo are used to detect the echo components in the filtered full-waveform echo. Lastly, particle swarm optimization (PSO) is used to remove the noise-caused echo components and optimize the parameters of the most probable echo components. Simulation results show that the wavelet-decomposition-based filter is of the best improvement of SNR and decomposition success rates than Wiener and Gaussian smoothing filters. In addition, the noise level estimated using wavelet-decomposition-based filter is more accurate than those estimated using other two commonly used methods. Experiments were carried out to evaluate the proposed method that was compared with our previous method (called GS-LM for short). In experiments, a lab-build full-waveform LiDAR system was utilized to provide eight types of full-waveform echoes scattered from three objects at different distances. Experimental results show that the proposed method has higher success rates for decomposition of full-waveform echoes and more accurate parameters estimation for echo components than those of GS-LM. The proposed method based on wavelet decomposition and PSO is valid to decompose the more complicated full-waveform echoes for estimating the multi-level distances of the objects and measuring the properties of the objects in a laser footprint.

  18. Assessment of Lipid and Metabolite Changes in Obese Calf Muscle Using Multi-Echo Echo-planar Correlated Spectroscopic Imaging.

    Science.gov (United States)

    Nagarajan, Rajakumar; Carpenter, Catherine L; Lee, Cathy C; Michael, Navin; Sarma, Manoj K; Souza, Raissa; Xu, Edward; Velan, S Sendhil; Hahn, Theodore J; Go, Vay-Liang; Thomas, M Albert

    2017-12-11

    Obesity-related conditions including heart disease, stroke, and type 2 diabetes are leading causes of preventable death. Recent evidence suggests that altered myocellular lipid metabolism in obesity may lead to increased insulin resistance (IR) that predisposes to these disorders. To test the hypothesis that muscles rich in type I vs. type II muscle fibers would exhibit similar changes in intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) content in obesity, we utilized a new four-dimensional multi echo echo-planar correlated spectroscopic imaging technique that allows separate determination of IMCL and EMCL content in individual calf muscles in obese vs. normal healthy human subjects. Calf muscles were scanned in 32 obese and 11 healthy subjects using a 3T MRI/MRS scanner, and IR in the obese subjects was documented by glucose tolerance testing. In obese subjects, elevation of both IMCL and EMCL content was observed in the gastrocnemius and tibialis anterior muscles (with mixed type I and II fiber content), while a significant increase in only IMCL content (+48%, p muscle (predominantly type I fibers). These observations indicate unexpected differences in changes in myolipid metabolism in type I vs. type II rich muscle regions in obesity, perhaps related to IR, and warrant further investigation.

  19. Phytoremediation of heavy metal contaminated soil potential by woody plants on Tonglushan ancient copper spoil heap in China.

    Science.gov (United States)

    Kang, Wei; Bao, Jianguo; Zheng, Jin; Xu, Fen; Wang, Liuming

    2018-01-02

    Fast-growing metal-accumulating woody plants are considered potential candidates for phytoremediation of metals. Tonglushan mining, one of the biggest Cu production bases in China, presents an important source of the pollution of environment. The sample was collected at Tonglushan ancient copper spoil heap. The aims were to measure the content of heavy metal in the soil and woody plants and to elucidate the phytoremediation potential of the plants. The result showed that soil Cu, Cd and Pb were the main contamination, the mean contents of which were 3166.73 mg/kg, 3.66 mg/kg and 137.06 mg/kg respectively, which belonged to severe contamination. Fourteen species from 14 genera of 13 families were collected and investigated; except for Ligutrum lucidum, the other 13 woody plants species were newly recorded in this area. In addition, to assess the ability of metal accumulation of these trees, we proposed accumulation index. Data suggested that Platanus × acerilolia, Broussonetia papyrifera, Ligutrum lucidum, Viburnum awabuki, Firmiana simplex, Robina pseudoacacia, Melia azedarach and Osmanthus fragrans exhibited high accumulated capacity and strong tolerance to heavy metals. Therefore, Platanus × acerilolia and Broussonetia papyrifera can be planted in Pb contaminated areas; Viburnum awabuki, Firmiana simplex, Robina pseudoacacia and Melia azedarach are the suitable trees for Cd contaminated areas; Viburnum awabuki, Melia azedarach, Ligutrum lucidum, Firmiana simplex, Osmanthus fragrans and Robina pseudoacacia are appropriate to Cu, Pb and Cd multi-metal contaminated areas.

  20. Biosurfactant-producing bacterium, Pseudomonas aeruginosa MA01 isolated from spoiled apples: physicochemical and structural characteristics of isolated biosurfactant.

    Science.gov (United States)

    Abbasi, Habib; Hamedi, Mir Manochehr; Lotfabad, Tayebe Bagheri; Zahiri, Hossein Shahbani; Sharafi, Hakimeh; Masoomi, Fatemeh; Moosavi-Movahedi, Ali Akbar; Ortiz, Antonio; Amanlou, Massoud; Noghabi, Kambiz Akbari

    2012-02-01

    An extensive investigation was conducted to isolate indigenous bacterial strains with outstanding performance for biosurfactant production from different types of spoiled fruits, food-related products and food processing industries. An isolate was selected from 800 by the highest biosurfactant yield in soybean oil medium and it was identified by 16S rRNA and the two most relevant hypervariable regions of this gene; V3 and V6 as Pseudomonas aeruginosa MA01. The isolate was able to produce 12 g/l of a glycolipid-type biosurfactant and generally less efficient to emulsify vegetable oils compared to hydrocarbons and could emulsify corn and coconut oils more than 50%. However, emulsification index (E(24)) of different hydrocarbons including hexane, toluene, xylene, brake oil, kerosene and hexadecane was between 55.8% and 100%. The surface tension of pure water decreased gradually with increasing biosurfactant concentration to 32.5 mNm(-1) with critical micelle concentration (CMC) value of 10.1mg/l. Among all carbon substrates examined, vegetable oils were the most effective on biosurfactant production. Two glycolipid fractions were purified from the biosurfactant crude extracts, and FTIR and ES-MS were used to determine the structure of these compounds. The analysis indicated the presence of three major monorhamnolipid species: R(1)C(10)C(10), R(1)C(10)C(12:1), and R(1)C(10)C(12); as well as another three major dirhamnolipid species: R(2)C(10)C(10), R(2)C(10)C(12:1), and R(2)C(10)C(12). The strain sweep experiment for measuring the linear viscoelastic of biosurfactant showed that typical behavior characteristics of a weak viscoelastic gel, with storage modulus greater than loss modulus at all frequencies examined, both showing some frequency dependence. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Mycorrhizal status of plants in two successional stages on spoil heaps from fireloam mining in Lower Silesia (SW Poland

    Directory of Open Access Journals (Sweden)

    Dorota Kasowska

    2014-01-01

    Full Text Available The mycorrhizal status of two plant communities representing an initial stage (1-2 year-old and a 8-9-year-old stage of succession on spoil heaps from fireloam mining in Lower Silesia, Poland, was determined. In the initial stage, the mycorrhizal structures were not observed in 39% of the investigated species; they were members of the Polygonaceae, Chenopodiaceae and Poaceae families. The relative cover of non-mycorrhizal plants exceeded 50% and the major role was played by the Polygonum aviculare population, which predominated the whole community. Mycorrhizal species (arbuscular mycorrhizae contributed to 61 % of the composition of the initial phyto-coenosis. The most numerous taxa were those with 20-40% of the root length colonized, with a small number of arbuscules (0.2-3.1% of the root length containig arbuscules and no vesicles. In the advanced stage of succession, mycorrhizal plants definitely dominated and the major role was played by the Tussilago farfara population. Compared with the initial stage, the later one also harboured more plants with mycorrhizas occupied >40% of the root length, as well as containing numerous arbuscules (>20% of the root length and vesicles. The non-mycorrhizal species, i.e., Equisetum arvense and Poa compressa, represented 11 % o': the community composition and their relative cover amounted to 3%. Despite the relatively frequent occurrence of the arbuscular mycorrhizae in the initial stage of succession, the qualitative properties of the colonization indicated a low effectiveness of symbiosis. This could be caused by the lack of adaptation of the fungal symbiont to the edaphic conditions which were changed after disturbance.

  2. Comparison of Echo 7 field line length measurements to magnetospheric model predictions

    International Nuclear Information System (INIS)

    Nemzek, R.J.; Winckler, J.R.; Malcolm, P.R.

    1992-01-01

    The Echo 7 sounding rocket experiment injected electron beams on central tail field lines near L = 6.5. Numerous injections returned to the payload as conjugate echoes after mirroring in the southern hemisphere. The authors compare field line lengths calculated from measured conjugate echo bounce times and energies to predictions made by integrating electron trajectories through various magnetospheric models: the Olson-Pfitzer Quiet and Dynamic models and the Tsyganenko-Usmanov model. Although Kp at launch was 3-, quiet time magnetic models est fit the echo measurements. Geosynchronous satellite magnetometer measurements near the Echo 7 field lies during the flight were best modeled by the Olson-Pfitzer Dynamic Model and the Tsyganenko-Usmanov model for Kp = 3. The discrepancy between the models that best fit the Echo 7 data and those that fit the satellite data was most likely due to uncertainties in the small-scale configuration of the magnetospheric models. The field line length measured by the conjugate echoes showed some temporal variation in the magnetic field, also indicated by the satellite magnetometers. This demonstrates the utility an Echo-style experiment could have in substorm studies

  3. Using the Echo Nest's automatically extracted music features for a musicological purpose

    DEFF Research Database (Denmark)

    Andersen, Jesper Steen

    2014-01-01

    This paper sums up the preliminary observations and challenges encountered during my first engaging with the music intelligence company Echo Nest's automatically derived data of more than 35 million songs. The overall purpose is to investigate whether musicologists can draw benefit from Echo Nest...

  4. Investigations on resolution enhancement in EPR by means of electron spin echoes

    International Nuclear Information System (INIS)

    Merks, R.P.J.

    1979-01-01

    The electron spin echo technique has been applied in four types of experiments: the measurement of electric field induced shifts of the EPR line; the detection of electron spin echo ENDOR; a relaxation measurement and the measurement of hyperfine interactions via the nuclear modulation effect. (Auth.)

  5. Signal changes in gradient echo images of human brain induced by hypo- and hyperoxia

    DEFF Research Database (Denmark)

    Rostrup, Egill; Larsson, H B; Toft, P B

    1995-01-01

    The effect of hypoxia (inspired oxygen fraction, FiO2 of 10% and 16%) and hyperoxia (FiO2) of 100%) on gradient echo images of the brain using long echo times was investigated in six healthy volunteers (age 24-28 years). Different flip angles were used with an FiO2 of 10% to assess the importance...

  6. Variations in the occurrence of SuperDARN F region echoes

    Directory of Open Access Journals (Sweden)

    M. Ghezelbash

    2014-02-01

    Full Text Available The occurrence of F region ionospheric echoes observed by a number of SuperDARN HF radars is analyzed statistically in order to infer solar cycle, seasonal, and diurnal trends. The major focus is on Saskatoon radar data for 1994–2012. The distribution of the echo occurrence rate is presented in terms of month of observation and magnetic local time. Clear repetitive patterns are identified during periods of solar maximum and solar minimum. For years near solar maximum, echoes are most frequent near midnight during winter. For years near solar minimum, echoes occur more frequently near noon during winter, near dusk and dawn during equinoxes and near midnight during summer. Similar features are identified for the Hankasalmi and Prince George radars in the northern hemisphere and the Bruny Island TIGER radar in the southern hemisphere. Echo occurrence for the entire SuperDARN network demonstrates patterns similar to patterns in the echo occurrence for the Saskatoon radar and for other radars considered individually. In terms of the solar cycle, the occurrence rate of nightside echoes is shown to increase by a factor of at least 3 toward solar maximum while occurrence of the near-noon echoes does not significantly change with the exception of a clear depression during the declining phase of the solar cycle.

  7. Comparison between two.magnetic resonance sequences (spin-echo and gradient-echo) in the analysis of lesions of the knee joint meniscus

    International Nuclear Information System (INIS)

    Marti-Bonati, L.; Casillas, C.

    1999-01-01

    To compare the diagnostic reliability, the proportion of common diagnoses and the degree of agreement between the results of two magnetic resonance (MR) sequences in the diagnosis of lesions of the meniscus of the knee. One hundred consecutive patients were studied prospectively by MR (1,5 Teslas). All of them underwent T1-weighted spin-echo and T1 and T2-weighted gradient-echo sequences. The final diagnosis was based on the combined results of four imaging sequences. The sensitivity, specificity, positive predictive value (PPV) and negative predictive (NPV) in terms of the final diagnosis were calculated for each meniscus and MR technique. The chi.squared test and kappa test were employed for the statistical analysis. There were discrepancies between the final diagnosis and the spin-echo sequence in 4 cases and between the final diagnosis and the gradient-echo sequences in 5 Both spin-echo and gradient-echo sequences showed the same diagnostic reliabilities: sensitivity of 0.98, specificity of 0.99, PPV of 0.98 and NPV of 0.99. The correlation between the two sequences was highly significant (chi-squared, p < 0.001) with a very high rate of agreement (kappa=0.84). The two sequences can be considered equally reliable in the study of meniscal lesions. (Author) 7 refs

  8. CUTLASS HF radar observations of high-velocity E-region echoes

    Directory of Open Access Journals (Sweden)

    M. V. Uspensky

    Full Text Available A short event of high-velocity E-region echo observations by the Pykkvibaer HF radar is analysed to study echo parameters and the echo relation to the Farley-Buneman plasma instability. The echoes were detected in several beams aligned closely to the magnetic L-shell direction. Two echo groups were identified: one group corresponded to the classical type 1 echoes with velocities close to the nominal ion-acoustic speed of 400 ms1 , while the other group had significantly larger velocities, of the order of 700 ms1 . The mutual relationship between the echo power, Doppler velocity, spectral width and elevation angles for these two groups was studied. Plotting of echo parameters versus slant range showed that all ~700 ms1 echoes originated from larger heights and distances of 500–700 km, while all ~400 ms1 echoes came from lower heights and from farther distances; 700–1000 km. We argue that both observed groups of echoes occurred due to the Farley-Buneman plasma instability excited by strong ( ~70 mVm1 and uniformly distributed electric fields. We show that the echo velocities for the two groups were different because the echoes were received from different heights. Such a separation of echo heights occurred due to the differing amounts of ionospheric refraction at short and large ranges. Thus, the ionospheric refraction and related altitude modulation of ionospheric parameters are the most important factors to consider, when various characteristics of E-region decametre irregularities are derived from HF radar measurements.

    Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; polar ionosphere

  9. Improving impact-echo method by wavelet transform for infrastructure inspection

    International Nuclear Information System (INIS)

    Shyu, Hungfa; Pai, Yawdawn

    1998-01-01

    Impact-echo, either in time domain or frequency domain, is one of the methods commonly used to measure thickness or strength of concrete structures. However, due to the anisotropic characteristics of concrete, the back-wall echoes are often very difficult to identify,' from received noisy time domain signals, and it is also frequently difficult to select a dominant frequency peak on an impact-echo spectrum for thickness calculation. wavelet transform was explored to solve this problem. With assistance of this tool, received noisy time domain impact-echo signals can be transformed directly. Periodic patterns corresponding to the back-wall echoes of measured structure will emerge from a two dimensional scalogram which is the result obtained from a continuous wavelet transform (CWT). Consequently, thickness measurements for concrete structures become more confident and reliable. The effectiveness of wavelet transform for concrete structure measurements of some research nuclear reactors is discussed in this paper. (author)

  10. Characteristics of C-band meteorological radar echoes at Petrolina, Northeast Brazil

    Science.gov (United States)

    da Silva Aragão, Maria Regina; Correia, Magaly De Fatima; Alves de Araújo, Heráclio

    2000-03-01

    A unique set of C-band meteorological radar echoes is analyzed. The data were obtained in Petrolina (9°24S, 40°30W), located in the semi-arid region of Northeast Brazil, from January to June 1985. The characteristics analyzed are echo areas, types and patterns.As in other tropical areas of the world, echoes with an area100 km2 dominated, making up 53% of the total number of echoes while echoes with 100 km2Petrolina surface and upper air data enable speculation that a system of frontal origin penetrating the radar area provided the dynamical forcing to form the bands in June. All five distinct patterns were more frequent in the southeast quadrant of the radar coverage. It is hypothesized that this preferential location may be explained, among other factors, by the interaction between the smooth relief and moisture advection by the southeasterly trade winds.

  11. Enhanced Primary Care Treatment of Behavioral Disorders With ECHO Case-Based Learning.

    Science.gov (United States)

    Komaromy, Miriam; Bartlett, Judy; Manis, Kathryn; Arora, Sanjeev

    2017-09-01

    The Extension for Community Healthcare Outcomes (ECHO) model offers a way for primary care providers to develop expertise in addressing behavioral health issues of primary care patients. It provides an alternative to traditional continuing medical education (CME) for ongoing training and support for health care providers. ECHO uses videoconferencing to connect multiple primary care teams simultaneously with academic specialists and builds capacity via mentorship and case-based learning. ECHO aims to expand access to care by developing capacity to treat common, complex conditions in underserved areas. Participants in an integrated addictions and psychiatry teleECHO program reported that when they presented a patient case, the feedback they received was highly valuable and led them to change their care plans more than 75% of the time. ECHO is an effective model for teaching primary care teams about behavioral health and may be more effective than traditional CME approaches.

  12. Soil organic carbon and nitrogen accumulation on coal mine spoils reclaimed with maritime pine (Pinus pinaster Aiton) in Agacli-Istanbul.

    Science.gov (United States)

    Sever, Hakan; Makineci, Ender

    2009-08-01

    Mining operations on open coal mines in Agacli-Istanbul have resulted in the destruction of vast amounts of land. To rehabilitate these degraded lands, plantations on this area began in 1988. Twelve tree species were planted, however, the most planted tree species was maritime pine (Pinus pinaster Aiton). This study performed on 14 sample plots randomly selected in maritime pine plantations on coal mine soil/spoils in 2005. Soil samples were taken from eight different soil layers (0-1, 1-3, 3-5, 5-10, 10-20, 20-30, 30-40 and 40-50 cm) into the soil profile. On soil samples; fine soil fraction (carbon (C(org)) and total nitrogen (N(t)) contents were investigated, and results were compared statistically among soil layers. As a result, 17 years after plantations, total forest floor accumulation determined as 17,973.20 kg ha(-1). Total nitrogen and organic matter amounts of forest floor were 113.90 and 14,640.92 kg ha(-1) respectively. Among soil layers, the highest levels of organic carbon (1.77%) and total nitrogen (0.096%) and the lowest pH value (pH 5.38) were found in 0-1 cm soil layer, and the variation differs significantly among soil layers. Both organic carbon and total nitrogen content decreased, pH values increased from 0-1 to 5-10 cm layer. In conclusion, according to results obtained maritime pine plantations on coal mine spoils; slow accumulation and decomposition of forest floor undergo simultaneously. Depending on these changes organic carbon and total nitrogen contents increased in upper layer of soil/spoil.

  13. An overview on optimized NLMS algorithms for acoustic echo cancellation

    Science.gov (United States)

    Paleologu, Constantin; Ciochină, Silviu; Benesty, Jacob; Grant, Steven L.

    2015-12-01

    Acoustic echo cancellation represents one of the most challenging system identification problems. The most used adaptive filter in this application is the popular normalized least mean square (NLMS) algorithm, which has to address the classical compromise between fast convergence/tracking and low misadjustment. In order to meet these conflicting requirements, the step-size of this algorithm needs to be controlled. Inspired by the pioneering work of Prof. E. Hänsler and his collaborators on this fundamental topic, we present in this paper several solutions to control the adaptation of the NLMS adaptive filter. The developed algorithms are "non-parametric" in nature, i.e., they do not require any additional features to control their behavior. Simulation results indicate the good performance of the proposed solutions and support the practical applicability of these algorithms.

  14. Heavy ion collision evolution modeling with ECHO-QGP

    Science.gov (United States)

    Rolando, V.; Inghirami, G.; Beraudo, A.; Del Zanna, L.; Becattini, F.; Chandra, V.; De Pace, A.; Nardi, M.

    2014-11-01

    We present a numerical code modeling the evolution of the medium formed in relativistic heavy ion collisions, ECHO-QGP. The code solves relativistic hydrodynamics in (3 + 1)D, with dissipative terms included within the framework of Israel-Stewart theory; it can work both in Minkowskian and in Bjorken coordinates. Initial conditions are provided through an implementation of the Glauber model (both Optical and Monte Carlo), while freezeout and particle generation are based on the Cooper-Frye prescription. The code is validated against several test problems and shows remarkable stability and accuracy with the combination of a conservative (shock-capturing) approach and the high-order methods employed. In particular it beautifully agrees with the semi-analytic solution known as Gubser flow, both in the ideal and in the viscous Israel-Stewart case, up to very large times and without any ad hoc tuning of the algorithm.

  15. Charged questions concerning noctilucent clouds and polar mesospheric summer echoes

    Science.gov (United States)

    Gumbel, J.

    2012-12-01

    Noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE) are prominent phenomena related to ice layers in the Earth's atmosphere at 80-90 km. These phenomena have been recognized as important tracers for interactions and variability in this part of the atmosphere. In order to draw proper conclusions from global observations, a better understanding of the microphysics of mesospheric ice grains is needed. This presentation provides an overview of current research topics concerning NLC and PMSE, with an emphasis is on charging pocesses. NLC and PMSE coincide with the ionospheric D-region, thus constituting a weakly ionized dusty plasma. Prominent open questions concern the efficiency of charge capture and photoionization, the role of charges in ice nucleation, charge diffusion, and interactions between ice and meteoric material.

  16. Artificial intelligence for the EChO mission planning tool

    Science.gov (United States)

    Garcia-Piquer, Alvaro; Ribas, Ignasi; Colomé, Josep

    2015-12-01

    The Exoplanet Characterisation Observatory (EChO) has as its main goal the measurement of atmospheres of transiting planets. This requires the observation of two types of events: primary and secondary eclipses. In order to yield measurements of sufficient Signal-to-Noise Ratio to fulfil the mission objectives, the events of each exoplanet have to be observed several times. In addition, several criteria have to be considered to carry out each observation, such as the exoplanet visibility, its event duration, and no overlapping with other tasks. It is expected that a suitable mission plan increases the efficiency of telescope operation, which will represent an important benefit in terms of scientific return and operational costs. Nevertheless, to obtain a long term mission plan becomes unaffordable for human planners due to the complexity of computing the huge number of possible combinations for finding an optimum solution. In this contribution we present a long term mission planning tool based on Genetic Algorithms, which are focused on solving optimization problems such as the planning of several tasks. Specifically, the proposed tool finds a solution that highly optimizes the defined objectives, which are based on the maximization of the time spent on scientific observations and the scientific return (e.g., the coverage of the mission survey). The results obtained on the large experimental set up support that the proposed scheduler technology is robust and can function in a variety of scenarios, offering a competitive performance which does not depend on the collection of exoplanets to be observed. Specifically, the results show that, with the proposed tool, EChO uses 94% of the available time of the mission, so the amount of downtime is small, and it completes 98% of the targets.

  17. Trawling bats exploit an echo-acoustic ground effect

    Directory of Open Access Journals (Sweden)

    Sandor eZsebok

    2013-04-01

    Full Text Available A water surface acts not only as an optic mirror but also as an acoustic mirror. Echolocation calls emitted by bats at low heights above water are reflected away from the bat, and hence the background clutter is reduced. Moreover, targets on the surface create an enhanced echo. Here, we formally quantified the effect of the substrate and target height on both target detection and –discrimination in a combined laboratory and field approach with Myotis daubentonii. In a two-alternative, forced-choice paradigm, the bats had to detect a mealworm and discriminate it from an inedible dummy (20 mm PVC disc. Psychophysical performance was measured as a function of height above either smooth substrates (water or PVC or above a clutter substrate (artificial grass. At low heights above the clutter substrate (10, 20 or 35 cm, the bats’ detection performance was worse than above a smooth substrate. At a height of 50 cm, the substrate structure had no influence on target detection. Above the clutter surface, also target discrimination was significantly impaired with decreasing target height. A detailed analysis of the bats’ echolocation calls during target approach shows that above the clutter substrate, the bats produce calls with significantly higher peak frequency. Flight-path reconstruction revealed that the bats attacked an object from below over water but from above over a clutter substrate.These results are consistent with the hypothesis that trawling bats exploit an echo-acoustic ground effect, in terms of a spatio-temporal integration of direct reflections with indirect reflections from the water surface, to optimize prey detection and –discrimination not only for prey on the water but also for some range above.

  18. High signal intensity of fat on fast spin echo imaging

    International Nuclear Information System (INIS)

    Ogura, Akio; Yamazaki, Masaru; Hongoh, Takaharu; Inoue, Hiroshi; Ishikuro, Akihiro

    2000-01-01

    The fast spin echo (FSE) technique of producing T 2 -weighted images in greatly reduced imaging times has recently been used for routine clinical study. FSE images show contrast that is very similar in most tissues to that of conventional SE images. However, fat shows a high signal intensity that is influenced by j-coupling and the magnetization transfer effect. The purpose of this study was to assess whether the higher signal intensity of fat is different among MRI systems and to examine the effects of j-coupling and magnetization transfer on the high signal intensity of fat on FSE. The contrast in signal intensity between fat and water was measured for various echo train lengths (ETL) with and without multislicing on FSE using a contrast phantom. Measurements were obtained with four different MRI systems. In addition, the effective T 2 values of fat were calculated for the above conditions. Results indicated that contrast for fat and water was reduced with increased ETL and by using multislicing and was different among the four MRI systems. The effective T 2 values of fat were extended for increased ETL and were not dependent on multislicing. They also differed among the four MRI systems. The extent of effective T 2 values was affected by j-coupling. In this study, it was indicated that the degree of the high signal intensity of fat on FSE differed for different MRI systems. In addition, the reasons for the high signal intensity of fat on FSE were related to the effects of j-coupling and magnetization transfer. (author)

  19. Short echo time proton spectroscopy of the brain in healthy volunteers using an insert gradient head coil

    DEFF Research Database (Denmark)

    Gideon, P; Danielsen, E R; Schneider, M

    1995-01-01

    An insert gradient head coil with built-in X, Y, and Z gradients was used for localized proton spectroscopy in the brain of healthy volunteers, using short echo time stimulated echo acquisition mode (STEAM) sequences. Volume of interest size was 3.4 ml, repetition time was 6.0 s, and echo times...

  20. Endoluminal MR imaging of porcine gastric structure in vivo

    International Nuclear Information System (INIS)

    Yoshinaka, Hayato; Morita, Yoshinori; Matsuoka, Yuichiro

    2010-01-01

    Recently, several new endoscopic instruments have been developed. However, even with the full use of current modalities, the safety of endoscopic surgery is not guaranteed. Information regarding factors such as fibrosis and the blood vessels under the mucosa is very important for avoiding procedure-related complications. The aim of this study was to define the detailed anatomy of the gastric wall structure in vivo using original endoluminal radiofrequency coils for safer endoscopic therapy. Swine were used as the subjects and controlled with general anesthesia. Anatomical images were obtained with T1-weighted fast spin echo (T1FSE) and T2-weighted fast spin echo (T2FSE). Dynamic magnetic resonance (MR) angiography was also obtained with three-dimensional T1-weighted fast spoiled gradient recalled acquisition in the steady state (3D-DMRA) following the injection of hyaluronic acid sodium into the submucosal layer. Porcine gastric wall structure was visualized, and four layers were discriminated in the T1FSE and T2FSE images. The vascular structure was clearly recognized in the submucosa on 3D-DMRA. Endoluminal MR imaging was able to visualize the porcine stomach with similar quality to endoscopic ultrasonography imaging. Additionally, it was possible to visualize the vascular structures in the submucosal layer. This is the first report to show that blood vessels under the gastric mucosa can be depicted in vivo. (author)

  1. An experimental study on dredge spoil of estuarine sediments in the bay of seine (France): A morphosedimentary assessment

    Science.gov (United States)

    Marmin, Stella; Lesueur, Patrick; Dauvin, Jean Claude; Samson, Sandrine; Tournier, Patrice; Gallicher Lavanne, Albert; Dubrulle-Brunaud, Carole; Thouroude, Coralie

    2016-03-01

    Studies on the consequences of dredging on estuarine morphology and its sedimentary dynamics are common, but the impacts of dumping dredge spoil in coastal open settings are rarely found in scientific literature. An experimental study was conducted over the period 2012-2013 to monitor the physical impacts of dredged material dumped at two adjacent sites (one million cubic metres at each) on the inner shelf of the Bay of Seine in France (eastern part of the English Channel, La Manche). As recently reinforced in the EU Marine Strategy Framework Directive (MSFD), knowledge on the location and intensity of human impacts (e.g. on marine ecosystems) is critical for effective marine management and conservation. So, two methods of disposition were tested to evaluate the impacts of dumping on the environment and thus propose recommendations for future dumping. The strategy is based on a Before-After-Control-Impact (BACI) approach, in which the spatio-temporal variability was studied by analysing the morphological and sedimentological characteristics over a period of 28 months, from November 2011 to April 2014, also including recovery of the seafloor after cessation of the dumping activities. The first experimental dumping operation (MASED) was carried out regularly for 8 months at a single point and generating a conical deposit of 5 m in height, while the second dumping (MABIO) lasted for 12 months involving four steps in the dumping process. In the second case, a wider area was covered, leading to the formation of a smaller deposit of 2 m in height. The dumped deposits consisted of muddy fine sand, whereas the inner shelf seafloor in this area is covered with fine to medium sand. As a result, muddy fine sand accumulated at or near the two dumping sites, with a maximum mud (i.e. particles4 Φ) content of 50% compared tostudy area. For the latter, a spreading of fine particles was observed extending from the conical deposit towards the south west. To favour long

  2. Characteristics of N-Acylhomoserine Lactones Produced by Hafnia alvei H4 Isolated from Spoiled Instant Sea Cucumber

    Directory of Open Access Journals (Sweden)

    Hong-Man Hou

    2017-04-01

    Full Text Available This study aimed to identify N-acylhomoserine lactone (AHL produced by Hafnia alvei H4, which was isolated from spoiled instant sea cucumber, and to investigate the effect of AHLs on biofilm formation. Two biosensor strains, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens KYC55, were used to detect the quorum sensing (QS activity of H. alvei H4 and to confirm the existence of AHL-mediated QS system. Thin layer chromatography (TLC and high resolution triple quadrupole liquid chromatography/mass spectrometry (LC/MS analysis of the AHLs extracted from the culture supernatant of H. alvei H4 revealed the existence of at least three AHLs: N-hexanoyl-l-homoserine lactone (C6-HSL, N-(3-oxo-octanoyl-l-homoserine lactone (3-oxo-C8-HSL, and N-butyryl-l-homoserine lactone (C4-HSL. This is the first report of the production of C4-HSL by H. alvei. In order to determine the relationship between the production of AHL by H. alvei H4 and bacterial growth, the β-galactosidase assay was employed to monitor AHL activity during a 48-h growth phase. AHLs production reached a maximum level of 134.6 Miller unites at late log phase (after 18 h and then decreased to a stable level of about 100 Miller unites. AHL production and bacterial growth displayed a similar trend, suggesting that growth of H. alvei H4 might be regulated by QS. The effect of AHLs on biofilm formation of H. alvei H4 was investigated by adding exogenous AHLs (C4-HSL, C6-HSL and 3-oxo-C8-HSL to H. alvei H4 culture. Biofilm formation was significantly promoted (p < 0.05 by 5 and 10 µM C6-HSL, inhibited (p < 0.05 by C4-HSL (5 and 10 µM and 5 µM 3-oxo-C8-HSL, suggesting that QS may have a regulatory role in the biofilm formation of H. alvei H4.

  3. Study of susceptibility-induced artefacts in GRASE with different echo train length.

    Science.gov (United States)

    Allkemper, T; Reimer, P; Schuierer, G; Peters, P E

    1998-01-01

    The aim of this study was to evaluate the sensitivity of gradient-and-spin-echo (GRASE) sequences to susceptibility effects. GRASE sequences with 21 and 33 echoes per echo train were compared with a T2-weighted FSE sequence with an echo train length of 5 by means of MRI in phantoms, volunteers (n = 10), and patients (n = 19) with old hemorrhagic brain lesions. All experiments were performed on a 1.0-T clinical MR system (Impact Expert, Siemens AG, Erlangen, Germany) with constant imaging parameters. Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations, of brain areas with physiological iron deposition (red nucleus, substantia nigra), and of areas of old brain hemorrhage were calculated for FSE and GRASE pulse sequences. Areas of old brain hemorrhage were also qualitatively analyzed for the degree of visible susceptibility effects by blinded reading. The CNR of iron oxide tubes and iron-containing brain areas decreased with increasing echo trains of GRASE sequences. The CNR of GRASE sequences decreased when compared with CNR of their FSE counterparts (GRASE 21 echo trains 23.8 +/- 0.8, FSE 5 echo trains 26.7 +/- 0.9; p trains preferable when patients with intracranial hemorrhage are clinically evaluated.

  4. Time-dependent ultrasound echo changes occur in tendon during viscoelastic testing.

    Science.gov (United States)

    Duenwald-Kuehl, Sarah; Kobayashi, Hirohito; Lakes, Roderic; Vanderby, Ray

    2012-11-01

    The viscoelastic behavior of tendons has been extensively studied in vitro. A noninvasive method by which to acquire mechanical data would be highly beneficial, as it could lead to the collection of viscoelastic data in vivo. Our lab has previously presented acoustoelasticity as an alternative ultrasound-based method of measuring tendon stress and strain by reporting a relationship between ultrasonic echo intensity (B mode ultrasound image brightness) and mechanical behavior of tendon under pseudoelastic in vitro conditions [Duenwald, S., Kobayashi, H., Frisch, K., Lakes, R., and Vanderby Jr, R., 2011, "Ultrasound Echo is Related to Stress and Strain in Tendon," J. Biomech., 44(3), pp. 424-429]. Viscoelastic properties of the tendons were not examined in that study, so the presence of time-dependent echo intensity changes has not been verified. In this study, porcine flexor tendons were subjected to relaxation and cyclic testing while ultrasonic echo response was recorded. We report that time- and strain history-dependent mechanical properties during viscoelastic testing are manifested in ultrasonic echo intensity changes. We also report that the patterns of the echo intensity changes do not directly mimic the patterns of viscoelastic load changes, but the intensity changed in a repeatable (and therefore predictable) fashion. Although mechanisms need further elucidation, viscoelastic behavior can be anticipated from echo intensity changes. This phenomenon could potentially lead to a more extensive characterization of in vivo tissue behavior.

  5. Possibilities for production of medicinal aromatic plants on the spoil bank of the Pljevlja coal mine. Mogucnost gajenja ljekovitog i aromaticnog bilja na jalovistu rudnika uglja - Pljevlja

    Energy Technology Data Exchange (ETDEWEB)

    Memic, M.; Bajovic, L. (Rudnik Uglja Pljevlja (Yugoslavia))

    1990-01-01

    Presents results obtained from experimental recultivation of the Potrlica surface coal mine spoil bank (810 m elevation, continental climate) during 1986-1990. Two experimental fields - Potrlica-I (600 m[sup 2]) and Potrlica-II (300 m[sup 2]) - were prepared by spreading a 10-20 cm thick layer of low-quality soil over the marly waste of the spoil bank. Soil composition was: 2.10% and 74% Ca, 4.5% and 0.70% humus, l3.5% and 5.5% P[sub 2]O[sub 5] and 23.0% and 6.0% K[sub 2]O in Potrlica-I and II respectively. Soil pH values were 7.2 and 7.60; 500 kg/ha NPK (15:15:15) were spread. Seventeen species of aromatic and medicinal plants were grown. After four years the plants were classified into 3 groups (thriving, satisfactory and non-thriving). It was found that the following plants can yield satisfactory crops and profits: valeriana officinalis, hyssopus officinalis, artemis dracunculus, cynaris scolimus, foenculum vulgare and malva silvestris. Unsatisfactory results were obtained with melisa officinalis, coriandrum sativum, pimpinela anisum and angelica archangelica. Experiments will be continued.

  6. Restoration Practices Used on Post Mining Sites and Industrial Deposits in the Czech Republic with an Example of Natural Restoration of Granodiorite Quarries and Spoil Heaps

    Directory of Open Access Journals (Sweden)

    Chuman Tomáš

    2015-11-01

    Full Text Available Mining of minerals that have significant impact on landscape and landscape functions affects 1% of the land surface worldwide. In the Czech Republic the extent of mining sites is estimated to be more than 800 km2 and according to the state legislation the land affected by mining should be reclaimed. There are several approaches to land restoration, which are shortly reviewed in this article, from pure technical approach to one adopting natural processes. The review shows increasing appeal of scientist and conservationist to use natural processes e.g. natural or directed succession as an alternative method of post-mining sites or industrial deposits restoration due to growing evidence of conservational value of such sites in human dominated landscapes. The natural processes used for land restoration are often argued to be slow therefore the rate of spontaneous vegetation succession was assessed in stone quarries and on spoil heaps using a sequence of panchromatic aerial images. The results showed that natural processes act fast and vegetation can reach 100% cover within 10-15 years in granodiorite quarries and on spoil heaps.

  7. Comparing the efficacy of solid and magic-echo refocusing sequences: Applications to1H NMR echo spectroscopy of shale rock.

    Science.gov (United States)

    Boutis, Gregory S; Kausik, Ravinath

    2017-11-01

    Quantitative evaluation of the solid and viscous components of unconventional shale rock, namely kerogen and bitumen, is important for understanding reservoir quality. Short transverse coherence times, due to strong 1 H- 1 H dipolar interactions, motivates the application of solid state refocusing pulse sequences that allow for investigating components of the free-induction decay that are otherwise obscured by instrumental effects such as probe ringdown. This work reports on static, wide-line 1 H spectroscopy of shale rock and their extracted components, which include kerogen and bitumen, by the application of solid echo and magic echo pulse sequences. We characterize the efficiency of these cycles as a function of the radio frequency power and inter-pulse spacing. Magic echos are shown to provide superior refocusing in comparison to solid echo based experiments, as can be understood from the truncation of the Magnus expansion and ability to also refocus any I z Hamiltonians (e.g. static field inhomogeneity). We characterize the optimal echo spacing and RF power for two shale samples of different maturity, motivating routine core and cuttings analysis and applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Realization of the revival of silenced echo (ROSE) quantum memory scheme in orthogonal geometry

    Science.gov (United States)

    Minnegaliev, M. M.; Gerasimov, K. I.; Urmancheev, R. V.; Moiseev, S. A.; Chanelière, T.; Louchet-Chauvet, A.

    2018-02-01

    We demonstrated quantum memory scheme on revival of silenced echo in orthogonal geometry in Tm3+: Y3Al5O12 crystal. The retrieval efficiency of ˜14% was demonstrated with the 36 µs storage time. In this scheme for the first time we also implemented a suppression of the revived echo signal by applying an external electric field and the echo signal has been recovered on demand if we then applied a second electric pulse with opposite polarity. This technique opens the possibilities for realizing addressing in multi-qubit quantum memory in Tm3+: Y3Al5O12 crystal.

  9. Wideband Radar Echo Frequency-domain Simulation and Analysis for High Speed Moving Targets

    Directory of Open Access Journals (Sweden)

    Ning Chao

    2014-04-01

    Full Text Available A frequency-domain method is proposed for wideband radar echo simulation of high-speed moving targets. Based on the physical process of electromagnetic waves observing a moving target, a frequency-domain echo model of wideband radar is constructed, and the block diagram of the radar echo simulation in frequency-domain is presented. Then, the impacts of radial velocity and slant range on the matching filtering of LFM radar are analyzed, and some quantitative conclusions on the shift and expansion of the radar profiles are obtained. Simulation results illustrate the correctness and efficiency of the proposed method.

  10. Masking Property Based Residual Acoustic Echo Cancellation for Hands-Free Communication in Automobile Environment

    Science.gov (United States)

    Lee, Yoonjae; Jeong, Seokyeong; Ko, Hanseok

    A residual acoustic echo cancellation method that employs the masking property is proposed to enhance the speech quality of hands-free communication devices in an automobile environment. The conventional masking property is employed for speech enhancement using the masking threshold of the desired clean speech signal. In this Letter, either the near-end speech or residual noise is selected as the desired signal according to the double-talk detector. Then, the residual echo signal is masked by the desired signal (masker). Experiments confirm the effectiveness of the proposed method by deriving the echo return loss enhancement and by examining speech waveforms and spectrograms.

  11. Significance of spin-echo intracardiac signal during cine cardiac MR imaging

    International Nuclear Information System (INIS)

    Feiglin, D.H.I.; O'Donnell, J.K.

    1987-01-01

    Thirty patient studies were performed using several multisection spin multi-echo pulse sequences (SEPS) formattable into the cine mode, with repetition time (TR)≤RR interval and 18 msec ≤ echo time (TE) ≤ 64 msec. Thirteen studies were performed in patients with various cardiomyopathies, ten in patients with cardiac tumors, and seven in healthy volunteers. The SEPS in the multi-echo acquisition format differentiated between tumor and stasis in terms of signal behavior. Healthy subjects may exhibit stasis of flow adjacent to the endocardium during the cardiac cycle

  12. Potential Usefulness of Flash-Induced Superluminal Light-Echo Pairs

    Science.gov (United States)

    Nemiroff, Robert J.; Zhong, Qi

    2016-01-01

    Astronomical flashes can create transient light-echo pair phenomena that have never yet been seen but might result in useful information, if found. Toward this end, it is first proven that all light-echo spots are intrinsically superluminal. The radial component of spot speeds toward an observer, however, may be subluminal, and spot pair creation and annihilation events will be observable, in theory, when spots cross the radial superluminal speed boundary. If found, these light-echo pairs could connect angular speeds to spatial speeds, which in turn could result in the recovery of absolute sizes, three-dimensional spatial orientations, and distances to astronomical objects. A hypothetical example is given.

  13. A Particle-in-Cell simulation of temporal plasma echo in the presence of Coulomb collisions

    Science.gov (United States)

    Wu, B. Z.; Nishimura, Y.; Wang, C. P.

    2017-10-01

    Particle-in-Cell simulation is developed to study temporal plasma echo of electron plasma wave. By imposing two external pulse electric fields to the plasma (pulse-like in time) the echo signal is observed. Coulomb collisional effect manifests itself as a shift of the echo peak and the damping of the peak amplitude, which can be seen by adding (rather phenomenological) frictional force to the electron equation of motion. A first principle based binary collision model is incorporated into the numerical simulation.

  14. Characterizing Polar Mesospheric Summer Echo Edge Effect Formation

    Science.gov (United States)

    Yee, J.; Bahcivan, H.

    2013-12-01

    Polar Mesospheric Summer Echoes (PMSEs) form in the summer mesopause region, between altitudes of 80 and 90 km. This phenomenon occurs in this region because of the extremely cold temperatures that allow for ice particles to develop, sediment, and grow to sizes as large as ~20 nm. Because these ice particles are immersed in the plasma of the D-region, electrons can attach to the ice surfaces and charge them. There are two trains of thought when it comes to the backscatter seen in sounding rocket and radar measurements of PMSEs. The first assumes that the structure of the PMSEs is driven by turbulent velocity fields and that radar detections are due to turbulent scattering. The second theory on the scatter from PMSE structures is that the echoes result from multiple sharp small-scale ledges that produce an edge scatter. In decomposing sounding rocket data, results have indicated that both scattering mechanisms play a role in PMSE backscatter. However, whereas the turbulent scatter theory is well developed, the physics behind the sharp-edge phenomena in the edge scattering theory has not been explained to date. We investigate the formation of the sharp edges in electron density detected by sounding rockets and in backscattered power detected by ground-based radars during PMSE regions by exploring the initial process by which PMSEs form using a one dimensional (1D) particle-in-cell (PIC) simulation. The simulation, adapted from the Plasma Theory and Simulation Group at UC Berkley, starts with the ice particles immersed in a warm electron-ion plasma and allows for the charging process of the ice particles. Starting with an initial Gaussian distribution of ice particles, we show that as the ice particles charge, they increase in mass more quickly (i.e. accumulate more electrons and ions) at the edges of the PMSE structure. This increased mass decreases the diffusion rates of the edges and 'freezes' the edges of the PMSE. This result demonstrates that the reason for the

  15. Homogeneity spoil spectroscopy

    International Nuclear Information System (INIS)

    Hennig, J.; Boesch, C.; Martin, E.; Grutter, R.

    1987-01-01

    One of the problems of in vivo MR spectroscopy of P-31 is spectra localization. Surface coil spectroscopy, which is the method of choice for clinical applications, suffers from the high-intensity signal from subcutaneous muscle tissue, which masks the spectrum of interest from deeper structures. In order to suppress this signal while maintaining the simplicity of surface coil spectroscopy, the authors introduced a small sheet of ferromagnetically dotted plastic between the surface coil and the body. This sheet destroys locally the field homogeneity and therefore all signal from structures around the coil. The very high reproducibility of the simple experimental procedure allows long-term studies important for monitoring tumor therapy

  16. Echoing echoes / Reet Sool

    Index Scriptorium Estoniae

    Sool, Reet, 1951-

    2003-01-01

    Kajastatakse ja analüüsitakse tudengite arvamusi, kes lugesid Lawrence Ferlinghetti luuletust "A report on a happening in Washington Square San Francisco" ilma autorit teadmata ; ka "autorist" üldisemalt kirjandusteooria seisukohalt

  17. High temporal resolution functional MRI using parallel echo volumar imaging

    International Nuclear Information System (INIS)

    Rabrait, C.; Ciuciu, P.; Ribes, A.; Poupon, C.; Dehaine-Lambertz, G.; LeBihan, D.; Lethimonnier, F.; Le Roux, P.; Dehaine-Lambertz, G.

    2008-01-01

    Purpose: To combine parallel imaging with 3D single-shot acquisition (echo volumar imaging, EVI) in order to acquire high temporal resolution volumar functional MRI (fMRI) data. Materials and Methods: An improved EVI sequence was associated with parallel acquisition and field of view reduction in order to acquire a large brain volume in 200 msec. Temporal stability and functional sensitivity were increased through optimization of all imaging parameters and Tikhonov regularization of parallel reconstruction. Two human volunteers were scanned with parallel EVI in a 1.5 T whole-body MR system, while submitted to a slow event-related auditory paradigm. Results: Thanks to parallel acquisition, the EVI volumes display a low level of geometric distortions and signal losses. After removal of low-frequency drifts and physiological artifacts,activations were detected in the temporal lobes of both volunteers and voxel-wise hemodynamic response functions (HRF) could be computed. On these HRF different habituation behaviors in response to sentence repetition could be identified. Conclusion: This work demonstrates the feasibility of high temporal resolution 3D fMRI with parallel EVI. Combined with advanced estimation tools,this acquisition method should prove useful to measure neural activity timing differences or study the nonlinearities and non-stationarities of the BOLD response. (authors)

  18. Stimulated nutation echo: application to the driven decoherence study

    Energy Technology Data Exchange (ETDEWEB)

    Bimbo, G [Istituto Nazionale per la Fisica della Materia and Department of Physical and Astronomical Sciences, University of Palermo, Via Archirafi 36, I 90123 Palermo (Italy); Boscaino, R [Istituto Nazionale per la Fisica della Materia and Department of Physical and Astronomical Sciences, University of Palermo, Via Archirafi 36, I 90123 Palermo (Italy); Cannas, M [Istituto Nazionale per la Fisica della Materia and Department of Physical and Astronomical Sciences, University of Palermo, Via Archirafi 36, I 90123 Palermo (Italy); Gelardi, F M [Istituto Nazionale per la Fisica della Materia and Department of Physical and Astronomical Sciences, University of Palermo, Via Archirafi 36, I 90123 Palermo (Italy); Shakhmuratov, R N [Kazan Physical Technical Institute of Russian Academy of Sciences, 10/7 Sibirski trakt, Kazan, 420029 (Russian Federation)

    2003-06-25

    We study experimentally the dynamical and decay properties of the stimulated nutation echo (SNE) in a two-level spin system, the signal of which allows the observation timescale of the driven coherence relaxation to be extended. This signal appears in the transient response of the system to the second pulse at time {tau}{sub 1} from its start and coinciding with the duration of the first pulse. The information about the first pulse duration is imprinted into the population difference of the inhomogeneously broadened ensemble of the two-level absorbers. The decay of the SNE signal has two contributions. One originates from the population decay during the time {tau} between the two pulses. Another is caused by the coherence loss during the excitation by the first pulse and the reading time of the second pulse. Experimental results on the decay properties induced by these mechanisms are presented for the first time. We investigate the dependence of these decay rates on the pulse intensity and we examine its relationship with the anomalous (non-Bloch) decay of other coherent transients in solids.

  19. Gradient Echo Quantum Memory in Warm Atomic Vapor

    Science.gov (United States)

    Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M.; Everett, Jesse L.; Higginbottom, Daniel; Campbell, Geoff T.; Lam, Ping Koy; Buchler, Ben C.

    2013-01-01

    Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain. PMID:24300586

  20. Body as Echoes: Cyber Archiving of Dazu Rock Carvings

    Science.gov (United States)

    Chen, W.-W.

    2017-08-01

    "Body As Echoes: Cyber Archiving of Dazu Rock Carvings (BAE project in short)" strives to explore the tangible/intangible aspects of digital heritage conservation. Aiming at Dazu Rock Carvings - World Heritage Site of Sichuan Province, BAE project utilizes photogrammetry and digital sculpting technique to investigate digital narrative of cultural heritage conservation. It further provides collaborative opportunities to conduct the high-resolution site survey for scholars and institutions at local authorities. For preserving and making sustainable of the tangible cultural heritage at Dazu Rock Carvings, BAE project cyber-archives the selected niches and the caves at Dazu, and transform them into high-resolution, three-dimensional models. For extending the established results and making the digital resources available to broader audiences, BAE project will further develop interactive info-motion interface and apply the knowledge of digital heritage from BAE project to STEM education. BAE project expects to bridge the platform for archeology, computer graphics, and interactive info-motion design. Digital sculpting, projection mapping, interactive info-motion and VR will be the core techniques to explore the narrative of digital heritage conservation. For further protecting, educating and consolidating "building dwelling thinking" through digital heritage preservation, BAE project helps to preserve the digital humanity, and reach out to museum staffs and academia. By the joint effort of global institutions and local authorities, BAE project will also help to foster and enhance the mutual understanding through intercultural collaborations.

  1. BODY AS ECHOES: CYBER ARCHIVING OF DAZU ROCK CARVINGS

    Directory of Open Access Journals (Sweden)

    W.-W. Chen

    2017-08-01

    Full Text Available “Body As Echoes: Cyber Archiving of Dazu Rock Carvings (BAE project in short” strives to explore the tangible/intangible aspects of digital heritage conservation. Aiming at Dazu Rock Carvings - World Heritage Site of Sichuan Province, BAE project utilizes photogrammetry and digital sculpting technique to investigate digital narrative of cultural heritage conservation. It further provides collaborative opportunities to conduct the high-resolution site survey for scholars and institutions at local authorities. For preserving and making sustainable of the tangible cultural heritage at Dazu Rock Carvings, BAE project cyber-archives the selected niches and the caves at Dazu, and transform them into high-resolution, three-dimensional models. For extending the established results and making the digital resources available to broader audiences, BAE project will further develop interactive info-motion interface and apply the knowledge of digital heritage from BAE project to STEM education. BAE project expects to bridge the platform for archeology, computer graphics, and interactive info-motion design. Digital sculpting, projection mapping, interactive info-motion and VR will be the core techniques to explore the narrative of digital heritage conservation. For further protecting, educating and consolidating “building dwelling thinking” through digital heritage preservation, BAE project helps to preserve the digital humanity, and reach out to museum staffs and academia. By the joint effort of global institutions and local authorities, BAE project will also help to foster and enhance the mutual understanding through intercultural collaborations.

  2. Gradient echo quantum memory in warm atomic vapor.

    Science.gov (United States)

    Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M; Everett, Jesse L; Higginbottom, Daniel; Campbell, Geoff T; Lam, Ping Koy; Buchler, Ben C

    2013-11-11

    Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain.

  3. Fast spin-echo MR imaging of the eye

    International Nuclear Information System (INIS)

    Hosten, N.; Lemke, A.J.; Bornfeld, N.; Wassmuth, R.; Schweiger, U.; Terstegge, K.; Felix, R.

    1996-01-01

    Magnetic resonance imaging of the eye usually includes T2-weighted images both for screening purposes and for characterization of melanoma. Conventional T2-weighted spin-echo (SE) imaging suffers both from long acquisition times and incomplete recovery of the virteous' signal. A fast SE sequence was therefore compared prospectively with conventional sequences in 29 consecutive patients with lesions of the eye. Fast SE images delineated melanoma and other lesions of the eye from vitreous better than conventional T2-weighted images. Image quality and lesion conspicuity were improved on the fast sequence. Whereas melanoma appeared hypointense to vitreous on both types of images, subretinal effusion was hypointense on fast images and hyperintense on conventional T2-weighted images. Ghosting of the globe, which, however, did not decrease diagnostic value, was more pronounced on fast images. Conventional T2-weighted images may be replaced by fast SE images in MR studies of the eye with a gain in lesion conspicuity and significant time saving. (orig.)

  4. Stimulated nutation echo: application to the driven decoherence study

    CERN Document Server

    Bimbo, G; Cannas, M; Gelardi, F M; Shakhmuratov, R N

    2003-01-01

    We study experimentally the dynamical and decay properties of the stimulated nutation echo (SNE) in a two-level spin system, the signal of which allows the observation timescale of the driven coherence relaxation to be extended. This signal appears in the transient response of the system to the second pulse at time tau sub 1 from its start and coinciding with the duration of the first pulse. The information about the first pulse duration is imprinted into the population difference of the inhomogeneously broadened ensemble of the two-level absorbers. The decay of the SNE signal has two contributions. One originates from the population decay during the time tau between the two pulses. Another is caused by the coherence loss during the excitation by the first pulse and the reading time of the second pulse. Experimental results on the decay properties induced by these mechanisms are presented for the first time. We investigate the dependence of these decay rates on the pulse intensity and we examine its relations...

  5. Polar mesosphere summer echoes during the July 2000 solar protonevent

    Directory of Open Access Journals (Sweden)

    V. Barabash

    2004-03-01

    Full Text Available The influence of the solar proton event (SPE 14–16 July 2000 on Polar Mesosphere Summer Echoes (PMSE is examined. PMSE were observed by the Esrange VHF MST Radar (ESRAD at 67°53'N, 21°06'E. The 30MHz Imaging Riometer for Ionospheric Studies IRIS in Kilpisjärvi (69°30'N, 20°47'E registered cosmic radio noise absorption caused by ionisation changes in response to the energetic particle precipitation. An energy deposition/ion-chemical model was used to estimate the density of free electrons and ions in the upper atmosphere. Particle collision frequencies were calculated from the MSISE-90 model. Electric fields were calculated using conductivities from the model and measured magnetic disturbances. The electric field reached a maximum of 91mV/m during the most intensive period of the geomagnetic storm accompanying the SPE. The temperature increase due to Joule and particle heating was calculated, taking into account radiative cooling. The temperature increase at PMSE heights was found to be very small. The observed PMSE were rather intensive and extended over the 80–90km height interval. PMSE almost disappeared above 86km at the time of greatest Joule heating on 15 July 2000. Neither ionisation changes, nor Joule/particle heating can explain the PMSE reduction. Transport effects due to the strong electric field are a more likely explanation. Key words. Meteorology and atmospheric dynamics (middle atmospheric dynamics, ionosphere (ionospheric disturbances; solar radiation and cosmic ray effects

  6. Networks of echoes imitation, innovation and invisible leaders

    CERN Document Server

    West, Bruce J; Grigolini, Paolo

    2014-01-01

    Networks of Echoes: Imitation, Innovation and Invisible Leaders is a mathematically rigorous and data rich book on a fascinating area of the science and engineering of social webs.  There are hundreds of complex network phenomena whose statistical properties are described by inverse power laws.  The phenomena of interest are not arcane events that we encounter only fleetingly, but are events that dominate our lives. We examine how this intermittent statistical behavior intertwines itself with what appears to be the organized activity of social groups.  The book is structured as answers to a sequence of questions such as: How are decisions reached in elections and boardrooms?  How is the stability of a society undermined by zealots and committed minorities, and how is that stability re-established?  Can we learn to answer such questions about human behavior by studying the way flocks of birds retain their formation when eluding a predator?  These questions and others are answered using a generic model of...

  7. MRI detection of hypointense brain lesions in patients with multiple sclerosis: T1 spin-echo vs. gradient-echo

    International Nuclear Information System (INIS)

    Dupuy, Sheena L.; Tauhid, Shahamat; Kim, Gloria; Chu, Renxin; Tummala, Subhash; Hurwitz, Shelley; Bakshi, Rohit

    2015-01-01

    Highlights: • Compared T1SE and T1GE in detecting hypointense brain lesions in MS patients. • T1GE detected a higher cerebral lesion volume and number than T1SE. • T1SE correlated significantly with disability, while T1GE did not. • Hypointense lesions on T1SE and T1GE are not interchangeable in patients with MS. - Abstract: Objective: Compare T1 spin-echo (T1SE) and T1 gradient-echo (T1GE) sequences in detecting hypointense brain lesions in multiple sclerosis (MS). Background: Chronic hypointense lesions on T1SE MRI scans are a surrogate of severe demyelination and axonal loss in MS. The role of T1GE images in the detection of such lesions has not been clarified. Design/methods: In 45 patients with MS [Expanded Disability Status Scale (EDSS) score (mean ± SD) 3.5 ± 2.0; 37 relapsing-remitting (RR); 8 secondary progressive (SP)], cerebral T1SE, T1GE, and T2-weighted fluid-attenuated inversion-recovery (FLAIR) images were acquired on a 1.5 T MRI scanner. Images were re-sampled to axial 5 mm slices before directly comparing lesion detectability using Jim (v.7, Xinapse Systems). Statistical methods included Wilcoxon signed rank tests to compare sequences and Spearman correlations to test associations. Results: Considering the entire cohort, T1GE detected a higher lesion volume (5.90 ± 6.21 vs. 4.17 ± 4.84 ml, p < 0.0001) and higher lesion number (27.82 ± 20.66 vs. 25.20 ± 20.43, p < 0.05) than T1SE. Lesion volume differences persisted when considering RR and SP patients separately (both p < 0.01). A higher lesion number by T1GE was seen only in the RR group (p < 0.05). When comparing correlations between lesion volume and overall neurologic disability (EDSS score), T1SE correlated with EDSS (Spearman r = 0.29, p < 0.05) while T1GE (r = 0.23, p = 0.13) and FLAIR (r = 0.24, p = 0.12) did not. Conclusion: Our data suggest that hypointense lesions on T1SE and T1GE are not interchangeable in patients with MS. Based on these results, we hypothesize that T1GE

  8. MRI detection of hypointense brain lesions in patients with multiple sclerosis: T1 spin-echo vs. gradient-echo

    Energy Technology Data Exchange (ETDEWEB)

    Dupuy, Sheena L.; Tauhid, Shahamat; Kim, Gloria; Chu, Renxin; Tummala, Subhash [Departments of Neurology, Brigham and Women' s Hospital, Laboratory for Neuroimaging Research, Partners MS Center, Harvard Medical School, Boston, MA (United States); Hurwitz, Shelley [Departments of Medicine, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Bakshi, Rohit, E-mail: rbakshi@bwh.harvard.edu [Departments of Neurology, Brigham and Women' s Hospital, Laboratory for Neuroimaging Research, Partners MS Center, Harvard Medical School, Boston, MA (United States); Departments of Radiology, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States)

    2015-08-15

    Highlights: • Compared T1SE and T1GE in detecting hypointense brain lesions in MS patients. • T1GE detected a higher cerebral lesion volume and number than T1SE. • T1SE correlated significantly with disability, while T1GE did not. • Hypointense lesions on T1SE and T1GE are not interchangeable in patients with MS. - Abstract: Objective: Compare T1 spin-echo (T1SE) and T1 gradient-echo (T1GE) sequences in detecting hypointense brain lesions in multiple sclerosis (MS). Background: Chronic hypointense lesions on T1SE MRI scans are a surrogate of severe demyelination and axonal loss in MS. The role of T1GE images in the detection of such lesions has not been clarified. Design/methods: In 45 patients with MS [Expanded Disability Status Scale (EDSS) score (mean ± SD) 3.5 ± 2.0; 37 relapsing-remitting (RR); 8 secondary progressive (SP)], cerebral T1SE, T1GE, and T2-weighted fluid-attenuated inversion-recovery (FLAIR) images were acquired on a 1.5 T MRI scanner. Images were re-sampled to axial 5 mm slices before directly comparing lesion detectability using Jim (v.7, Xinapse Systems). Statistical methods included Wilcoxon signed rank tests to compare sequences and Spearman correlations to test associations. Results: Considering the entire cohort, T1GE detected a higher lesion volume (5.90 ± 6.21 vs. 4.17 ± 4.84 ml, p < 0.0001) and higher lesion number (27.82 ± 20.66 vs. 25.20 ± 20.43, p < 0.05) than T1SE. Lesion volume differences persisted when considering RR and SP patients separately (both p < 0.01). A higher lesion number by T1GE was seen only in the RR group (p < 0.05). When comparing correlations between lesion volume and overall neurologic disability (EDSS score), T1SE correlated with EDSS (Spearman r = 0.29, p < 0.05) while T1GE (r = 0.23, p = 0.13) and FLAIR (r = 0.24, p = 0.12) did not. Conclusion: Our data suggest that hypointense lesions on T1SE and T1GE are not interchangeable in patients with MS. Based on these results, we hypothesize that T1GE

  9. 32 CFR 199.5 - TRICARE Extended Care Health Option (ECHO).

    Science.gov (United States)

    2010-07-01

    ... all authorized ECHO respite care services through established TRICARE claims' mechanisms. No special... under Title XIX of the Social Security Act (Medicaid). Rehabilitation and assistive technology services... care services through established TRICARE claims' mechanisms. No special billing arrangements will be...

  10. AFSC/ABL: Frederick Sound Echo-integrated Trawl Survey, 2001 to 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The acoustic trawl database for Frederick Sounds echo-trawl survey was conducted from 2001 to 2004. The surveys were conducted throughout most of the southern part...

  11. Numerical calculation of spin echo amplitude in pulsed NMR: effects of quadrupole interaction

    International Nuclear Information System (INIS)

    Sobral, R.R.

    1986-01-01

    The spin echo obtained by nuclear magnetic resonance, in systems which atomic nuclei interact with magnetic fields and electric field gradients, present oscillations in function of the time interval between two excitations pulses. Using the density matrix formalism, the amplitudes of these echo is calculated, analytically. In this work, echo amplitudes obtained under different excitation conditions for nuclei of different nuclear spin values are calculated. The numerical results are compared with disposable analytical solutions. Applications of this method to the case of electric field gradient without axial symmetry were studied. Within the used approximation limits, an expression for attnuation of oscillatory behaviour of echo amplitude in function of the time interval between experimentally observed pulses was obtained. (M.C.K.) [pt

  12. Worldwide Echo-Sounding Correction Tables to Convert to Standard Velocity Depths

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Echo-sounding tables (3rd Edition) were prepared by D.J.T. Carter of the Marine Information and Advisory Service (United Kingdom) for the conversion of raw...

  13. AFSC/ABL: Lynn Canal Echo-Integrated Trawl Surveys, 2001-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The acoustic trawl database for Lynn Canals echo-trawl survey was conducted from 2001 to 2004 throughout southern Lynn Canal in southeast Alaska. Acoustic surveys...

  14. Seafloor classification using echo- waveforms: A method employing hybrid neural network architecture

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Mahale, V.; DeSouza, C.; Das, P.

    This letter presents seafloor classification study results of a hybrid artificial neural network architecture known as learning vector quantization. Single beam echo-sounding backscatter waveform data from three different seafloors of the western...

  15. Mono-Exponential Fitting in T2-Relaxometry: Relevance of Offset and First Echo.

    Directory of Open Access Journals (Sweden)

    David Milford

    Full Text Available T2 relaxometry has become an important tool in quantitative MRI. Little focus has been put on the effect of the refocusing flip angle upon the offset parameter, which was introduced to account for a signal floor due to noise or to long T2 components. The aim of this study was to show that B1 imperfections contribute significantly to the offset. We further introduce a simple method to reduce the systematic error in T2 by discarding the first echo and using the offset fitting approach.Signal curves of T2 relaxometry were simulated based on extended phase graph theory and evaluated for 4 different methods (inclusion and exclusion of the first echo, while fitting with and without the offset. We further performed T2 relaxometry in a phantom at 9.4T magnetic resonance imaging scanner and used the same methods for post-processing as in the extended phase graph simulated data. Single spin echo sequences were used to determine the correct T2 time.The simulation data showed that the systematic error in T2 and the offset depends on the refocusing pulse, the echo spacing and the echo train length. The systematic error could be reduced by discarding the first echo. Further reduction of the systematic T2 error was reached by using the offset as fitting parameter. The phantom experiments confirmed these findings.The fitted offset parameter in T2 relaxometry is influenced by imperfect refocusing pulses. Using the offset as a fitting parameter and discarding the first echo is a fast and easy method to minimize the error in T2, particularly for low to intermediate echo train length.

  16. Spontaneous cerebral microbleeds on gradient echo MR imaging in the stroke patients

    International Nuclear Information System (INIS)

    Kwak, Seong Ho; Song, Chang June; Kim, Dae Bong; Jeong, Geum Chae

    2003-01-01

    To investigate the spontaneous cerebral microbleeding occurring at gradient-echo MRI, and its relationship with associated stroke lesions and risk factors. Between September 2001 and December, 2002, 32 patients (21 men and 11 women; mean age 63 years) in whom cerebral microbleeding occurred at gradient-echo MRI were retrospectively investigated. Using a 1.5T MR imager, spin-echo T1-weighted, fast spin-echo T2-weighted, diffusion-weighted, and gradient-echo images were obtained. The number and location of microbleeds seen on gradient echo images, patients data, and associated stroke lesions such as intracerebral hemorrhage and lacunar and territorial infarction were assessed. Among the 32 patients, 563 microbleeds and between 1 and 66 (mean, 17.6) were noted at gradient-echo imaging. Microbleeding occurred in the cortical/subcortical area (n=216), the basal ganglia (n=173), thalamus (n=92), cerebellum (n=41), brainstem (n=36) and corpus callosum (n=1), and in 20 patients was bilateral. Patients had a history of hypertension (n=26), hypertriglycemia (n=12), heart disease (n=4), and diabetes mellitus (n=3). Stroke lesions were seen in 27 patients, intracerebral hemorrhage in ten, lacunar infarction in 24, and territorial infarction in four. The incidence and number of microbleeds was greater in older patients and in those with hypertension, hypertriglycemia, and stroke lesions such as intracerebral hemorrhage or lacunar infarction. The detection of microbleeding at gradient-echo imaging is helpful, since it predicts the possibility of cerebral hemorrhage in these patients

  17. Spontaneous cerebral microbleeds on gradient echo MR imaging in the stroke patients

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Seong Ho; Song, Chang June; Kim, Dae Bong; Jeong, Geum Chae [Chungnam National University College of Medicine, Taejon (Korea, Republic of)

    2003-08-01

    To investigate the spontaneous cerebral microbleeding occurring at gradient-echo MRI, and its relationship with associated stroke lesions and risk factors. Between September 2001 and December, 2002, 32 patients (21 men and 11 women; mean age 63 years) in whom cerebral microbleeding occurred at gradient-echo MRI were retrospectively investigated. Using a 1.5T MR imager, spin-echo T1-weighted, fast spin-echo T2-weighted, diffusion-weighted, and gradient-echo images were obtained. The number and location of microbleeds seen on gradient echo images, patients data, and associated stroke lesions such as intracerebral hemorrhage and lacunar and territorial infarction were assessed. Among the 32 patients, 563 microbleeds and between 1 and 66 (mean, 17.6) were noted at gradient-echo imaging. Microbleeding occurred in the cortical/subcortical area (n=216), the basal ganglia (n=173), thalamus (n=92), cerebellum (n=41), brainstem (n=36) and corpus callosum (n=1), and in 20 patients was bilateral. Patients had a history of hypertension (n=26), hypertriglycemia (n=12), heart disease (n=4), and diabetes mellitus (n=3). Stroke lesions were seen in 27 patients, intracerebral hemorrhage in ten, lacunar infarction in 24, and territorial infarction in four. The incidence and number of microbleeds was greater in older patients and in those with hypertension, hypertriglycemia, and stroke lesions such as intracerebral hemorrhage or lacunar infarction. The detection of microbleeding at gradient-echo imaging is helpful, since it predicts the possibility of cerebral hemorrhage in these patients.

  18. Preference of echo features for classification of seafloor sediments using neural networks

    Digital Repository Service at National Institute of Oceanography (India)

    De, C.; Chakraborty, B.

    :2722- 2725. Chakraborty, B., V. Kodagali, and J. Baracho. 2003. Sea-floor classification using multibeam echo-sounding angular backscatter data: A real-time approach emplying hybrid neural network architecture. IEEE Journal of Oceanic Enggineering 28... echo-waveforms: A method employing hybrid neural network architecture. IEEE Geoscience and Remote Sensing Letters 1: 196-200. Chakraborty, B., V. Mahale, G. Navelkar, B. R. Rao, R. G. Prabhudesai, B. Ingole, and G. Janakiraman. 2007. Acoustic...

  19. MR cholangiopancreatography : comparison of breath-hold fast spin echo and respiratory triggered fast spin echo techniques

    International Nuclear Information System (INIS)

    Kim, Myeong Jin; Hong, Hye Suk; Chung, Jae Joon; Chung, Jae Bock; Yang, Hee Chul; Yoo, Hyung Sik; Lee, Jaong Tae

    1997-01-01

    To determine relative image qualities and to evaluate their ability to visualize biliary trees and pancreatic ducts, we compared the breath-hold fast echo (FSE) and respiratory-triggered FSE technique in magnetic resonance cholangiopancreatography (MRCP). Forty-seven patients with suspected of hepatic disease but no pancreatic or biliary ductal dilatation, as determined by other imaging techniques (group of non-pathologic pancreatobiliary tree), and seven with pancreatic or biliary disease (group of pathologic pancreatobiliary tree) underwent MRCP. Heavily T2-weighted FSE coronal images were obtained by both breath-hold and respiratory triggered techniques. These two images were 3 D-reconstructed using a maximal intensity projection algorithm. Three radiologists scored the image qualities of anatomic by the two techniques. For the visualization of extrahepatic bile ducts, the respiratory triggered FSE sequence was better than the breath-hold sequence; for the evaluation of both a non-dilated and dilated pancreatobiliary system, however, both techniques need further development. (author). 16 refs., 2 tabs., 4 figs

  20. Utility of echo-planar gradient-echo T2*-weighted MR images in patients with primary intracerebral hemorrhage

    International Nuclear Information System (INIS)

    Yokoe, Toshio; Yoshida, Tazuka; Kobayashi, Nozomu; Nakamura, Yukihiro; Kubota, Kazuyuki

    2005-01-01

    Magnetic resonance imaging (MRI) has the potential to reveal residues of intracerabral hemorrhage (ICH) throughout life because of the high sensitivity for iron-containing compounds. Gradient-echo T2 * -weighted MR imaging (T2 * MRI) requiring short times for complete acquisition is known to detect small areas of signal loss without surrounding edema representing microbleeds (MBs). MBs in the basal ganglia including the thalami are suggested to be closely related to intracerebral atherosclerotic microangiopathy. We looked for more than 3 MBs in basal ganglia or thalamus of patients with and without episodes of previous ICH. Twelve patients with previous hemorrhagic stroke and 82 without were studied. Multiple MBs in those regions were significantly more frequent in patients with recurrent ICH. In addition, a 76-year-old woman with a history of hypertension was transferred to our hospital for treatment of head injury. She had multiple incidental old basal ganglionic and thalamic MBs. The patient had an asymptomatic primary ICH on computed tomography (CT) 3 months later. In conclusion, MR evidence of multiple MBs in the basal ganglia and thalamus might identify patients at a risk for new and recurrent ICH. Therefore, patients with multiple MBs in those regions should be treated for cerebrovascular risk factors, especially hypertension. Our results appear to confirm the utility of T2 * MRI in hemorrhagic stroke. (author)

  1. Performance Analysis for Acoustic Echo Cancellation Systems based on Variable Step Size NLMS algorithms

    Science.gov (United States)

    Hegde, Rajeshwari; Balachandra, K.; Rao, Madhusudhan

    2011-12-01

    Acoustic echo cancellation is an essential signal enhancement tool in hands-free communication. Loudspeaker signals are picked up by a microphone and are fed back to the correspondent, resulting in an undesired echo. Nowadays, adaptive filtering techniques are typically employed to suppress this echo. In acoustic applications long filters need to be adapted for sufficient echo suppression. Classical adaptation schemes such as LMS are quite expensive for accurate echo path modeling in highly reverberating environments. In order to cope with dynamic signals, step-size μ is often normalized by taking it inversely proportional to the energy of x. This normalized version of LMS (NLMS) is typically used in practice. This paper discusses various variable step-size NLMS based algorithms which can be implemented in acoustic echo cancelling applications. The performance of these algorithms in terms of ERLE and NSEC curves are obtained and comparison between them is done. Also a simple and novel Double-Talk Detection scheme is proposed in this paper.

  2. A comparison between fast and conventional spin-echo in the detection of multiple sclerosis lesions

    International Nuclear Information System (INIS)

    Thorpe, J.W.; Halpin, S.F.; MacManus, D.G.; Barker, G.J.; Kendall, B.E.; Miller, D.H.

    1994-01-01

    Long repetition time (TR) spin-echo (SE) with T 2 - or proton density weighting is the sequence of choice to detect the brain lesions of multiple sclerosis (MS). Fast spin-echo (FSE) permits the generation of T 2 -weighted images with similar contrast to SE but in a fraction of the time. We compared the sensitivity of FSE and SE in the detection of the brain lesions of MS. Six patients with clinically definite MS underwent brain imaging with both dual echo (long TR, long and short echo time (TE) SE and dual echo FSE. The SE and FSE images were first reviewed independently and then compared. A total of 404 lesions was detected on SE and 398 on FSE. Slightly more periventricular lesions were detected using SE than FSE (145 vs 127), whereas more posterior cranial fossa lesions were detected by FSE (77 vs 57). With both SE and FSE the short TE images revealed more lesions than the long echo. These results suggest that FSE could replace SE as the long TR sequence of choice in the investigation of MS. (orig.)

  3. Pre-ejection period by radial artery tonometry supplements echo doppler findings during biventricular pacemaker optimization

    Directory of Open Access Journals (Sweden)

    Qamruddin Salima

    2011-07-01

    Full Text Available Abstract Background Biventricular (Biv pacemaker echo optimization has been shown to improve cardiac output however is not routinely used due to its complexity. We investigated the role of a simple method involving computerized pre-ejection time (PEP assessment by radial artery tonometry in guiding Biv pacemaker optimization. Methods Blinded echo and radial artery tonometry were performed simultaneously in 37 patients, age 69.1 ± 12.8 years, left ventricular (LV ejection fraction (EF 33 ± 10%, during Biv pacemaker optimization. Effect of optimization on echo derived velocity time integral (VTI, ejection time (ET, myocardial performance index (MPI, radial artery tonometry derived PEP and echo-radial artery tonometry derived PEP/VTI and PEP/ET indices was evaluated. Results Significant improvement post optimization was achieved in LV ET (286.9 ± 37.3 to 299 ± 34.6 ms, p Conclusion An acute shortening of PEP by radial artery tonometry occurs post Biv pacemaker optimization and correlates with improvement in hemodynamics by echo Doppler and may provide a cost-efficient approach to assist with Biv pacemaker echo optimization.

  4. Slow flow and mural thrombus in aortic diseases: Spin-echo MR findings and their differentiation

    International Nuclear Information System (INIS)

    Chung, Jin Wook; Park, Jae Hyung; Han, Man Chung

    1993-01-01

    In order to evaluate the ability of spin-echo MR imaging to differentiate slow flow from mural thrombus in aortic diseases, we reviewed the spin-echo MR images of 13 patients with intraaortic thrombus documented by CT (N=11) or aortography (N=2). Six patients had aortic aneurysms and seven had aortic dissections. Intraaortic mural thrombi were accompanied by flow-related intraluminal signal of various pattern and extents in all 13 patients. On 10 gated MR studies, slow flow regions showed ever-echo rephasing phenomenon (N=8), interslice variation of signal intensities of the intraluminal signal (N=7) and flow-related ghost artifact (N=2). However, these MR flow phenomena were obscured on two of three non-gated studies. Seven of 13 intraaortic thrombi remained hyperintense on T2-weighted second-echo images. In these circumstance, a hypointense boundary layer between slow flow and mural thrombus, which was caused by either ' boundary layer dephasing phenomenon' of slow flow or 'paramagnetic T2 shortening' of fresh clot at the edge of mural thrombus, was very useful in discriminating the area of slow flow from that of mural thrombus. Proper interpretation of spin-echo MR images may obviate the need for phase display imaging or gradient-echo imaging in differentiating slow flow and mural thrombus

  5. Software Applications to Access Earth Science Data: Building an ECHO Client

    Science.gov (United States)

    Cohen, A.; Cechini, M.; Pilone, D.

    2010-12-01

    Historically, developing an ECHO (NASA’s Earth Observing System (EOS) ClearingHOuse) client required interaction with its SOAP API. SOAP, as a framework for web service communication has numerous advantages for Enterprise applications and Java/C# type programming languages. However, as interest has grown for quick development cycles and more intriguing “mashups,” ECHO has seen the SOAP API lose its appeal. In order to address these changing needs, ECHO has introduced two new interfaces facilitating simple access to its metadata holdings. The first interface is built upon the OpenSearch format and ESIP Federated Search framework. The second interface is built upon the Representational State Transfer (REST) architecture. Using the REST and OpenSearch APIs to access ECHO makes development with modern languages much more feasible and simpler. Client developers can leverage the simple interaction with ECHO to focus more of their time on the advanced functionality they are presenting to users. To demonstrate the simplicity of developing with the REST API, participants will be led through a hands-on experience where they will develop an ECHO client that performs the following actions: + Login + Provider discovery + Provider based dataset discovery + Dataset, Temporal, and Spatial constraint based Granule discovery + Online Data Access

  6. Coherent control of light pulses stored in a Gradient Echo Memory

    Science.gov (United States)

    Carreño, F.; Antón, M. A.

    2011-06-01

    We address the problem of storage and retrieval of a time-bin qubit onto an atomic ensemble of three-level atoms of the Λ - type driven by a far detuned coupling field. The atoms are subject to a longitudinal magnetic field which produces a spatially varying Zeeman splitting of the lower levels along the medium and allows for the spatial encoding of the different angular frequencies of the input pulse during the storage phase. The system operates like a quantum optical memory which is referred to as Gradient Echo Memory (GEM) in analogy to the NMR gradient echo. In the conventional approach to GEM-based devices in Λ - type media, the coupling field co-propagates with the probe field and the magnetic field is reversed after the storage phase, thus an echo signal is released from the medium in the forward direction, in contrast to π-pulse based echo memories which produce a time reversed echo signal in the backward direction. In this work we predict that a backward echo pulse can also be obtained in a GEM schema by making use of a counter-propagating coupling field during the reading phase of the process. In addition, we show that for a proper engineering of the control parameters the system can act as an optical router, i.e., part of the stored signal can be released in the forward direction and the rest in the backward one. The current proposal could have potential applications in quantum information processing.

  7. Polar mesosphere summer echoes (PMSE) a southern hemisphere perspective

    Science.gov (United States)

    Morris, R. J.; Murphy, D. J.; Klekociuk, A. R.; Holdsworth, D. A.

    The existence of Polar Mesosphere Summer Echoes PMSE in the Southern Hemisphere SH has recently been confirmed using HF radar Ogawa et al 2002 MST radar Morris et al 2004 and a Dynasonde Jarvis et al 2005 following earlier observations using MST radar Woodman et al 1999 These studies spanned the geographic latitudes 62 1 r S Machu Picchu 68 6 r S Davis 69 0 r S Syowa and 75 5 r S Halley Bay The emerging array of SH SuperDARN radars provide an opportunity to extend the spatial coverage of PMSE observations An understanding of the occurrence and intensity of PMSE against latitude in the SH is needed to facilitate a comparison with the better spatial coverage of Northern Hemisphere NH PMSE observations Such a comparison will contribute to the ongoing debate as to whether PMSE can provide a proxy for mesosphere temperature and thus shed light on the existence of any interhemispheric asymmetry or otherwise in the polar mesosphere regions The argument for different polar mesosphere environments spawned in part by the reported lack of SH PMSE observations Recent PMSE reflectivity and intensity results from Davis 68 6 r S and Andenes 69 0 r N are given The characteristics and morphology of PMSE events above these Antarctic stations are considered in the context of the thermal and dynamical state of the mesosphere as deduced from satellite i e SABER and AURA and radar i e MF and MST observations respectively A brief account of recent coincident PMSE MST radar and Polar Mesospheric Cloud PMC

  8. Dynamic echo information guides flight in the big brown bat

    Directory of Open Access Journals (Sweden)

    Michaela eWarnecke

    2016-04-01

    Full Text Available Animals rely on sensory feedback from their environment to guide locomotion. For instance, visually guided animals use patterns of optic flow to control their velocity and to estimate their distance to objects (e.g. Srinivasan et al. 1991, 1996. In this study, we investigated how acoustic information guides locomotion of animals that use hearing as a primary sensory modality to orient and navigate in the dark, where visual information is unavailable. We studied flight and echolocation behaviors of big brown bats as they flew under infrared illumination through a corridor with walls constructed from a series of individual vertical wooden poles. The spacing between poles on opposite walls of the corridor was experimentally manipulated to create dense/sparse and balanced/imbalanced spatial structure. The bats’ flight trajectories and echolocation signals were recorded with high-speed infrared motion-capture cameras and ultrasound microphones, respectively. As bats flew through the corridor, successive biosonar emissions returned cascades of echoes from the walls of the corridor. The bats flew through the center of the corridor when the pole spacing on opposite walls was balanced and closer to the side with wider pole spacing when opposite walls had an imbalanced density. Moreover, bats produced shorter duration echolocation calls when they flew through corridors with smaller spacing between poles, suggesting that clutter density influences features of the bat’s sonar signals. Flight speed and echolocation call rate did not, however, vary with dense and sparse spacing between the poles forming the corridor walls. Overall, these data demonstrate that bats adapt their flight and echolocation behavior dynamically when flying through acoustically complex environments.

  9. Occurrence of polar mesosphere summer echoes at very high latitudes

    Directory of Open Access Journals (Sweden)

    M. Zecha

    2009-03-01

    Full Text Available Observations of polar mesosphere summer echoes (PMSE have been carried out during the summer periodes 1999–2001 and 2003–2004 at the very high latitude of 78° N using the SOUSY Svalbard Radar (53.5 MHz at Longyearbyen. Although the measurements could not be done continuously in these seasons, PMSE have been detected over more than 6600 h of 9300 h of observation time overall. Using this data base, particular PMSE occurrence characteristics have been determined. PMSE at Svalbard appear from the middle of May to the end of August with an almost permanent total occurrence in June and July. Diurnal variations are observable in the height-depend occurrence rates and in PMSE thickness, they show a maximum around 09:00–10:00 UTC and a minimum around 21:00–22:00 UTC. PMSE occur nearly exclusively between a height of 80 km and 92 km with a maximum near 85 km. However, PMSE appear not simultaneously over the entire height range, the mean vertical PMSE extension is around 4–6 km in June and July. Furthermore, typically PMSE are separated into several layers, and only 30% of all PMSE are single layers. The probability of multiple layers is greater in June and July than at the beginning and the end of the PMSE season and shows a marked 5-day-variation. The same variation is noticeable in the seasonal dependence of the PMSE occurrence and the PMSE thickness. We finally discuss potential geophysical processes to explain our observational results.

  10. Polar mesosphere summer echoes during the July 2000 solar protonevent

    Directory of Open Access Journals (Sweden)

    V. Barabash

    2004-03-01

    Full Text Available The influence of the solar proton event (SPE 14–16 July 2000 on Polar Mesosphere Summer Echoes (PMSE is examined. PMSE were observed by the Esrange VHF MST Radar (ESRAD at 67°53'N, 21°06'E. The 30MHz Imaging Riometer for Ionospheric Studies IRIS in Kilpisjärvi (69°30'N, 20°47'E registered cosmic radio noise absorption caused by ionisation changes in response to the energetic particle precipitation. An energy deposition/ion-chemical model was used to estimate the density of free electrons and ions in the upper atmosphere. Particle collision frequencies were calculated from the MSISE-90 model. Electric fields were calculated using conductivities from the model and measured magnetic disturbances. The electric field reached a maximum of 91mV/m during the most intensive period of the geomagnetic storm accompanying the SPE. The temperature increase due to Joule and particle heating was calculated, taking into account radiative cooling. The temperature increase at PMSE heights was found to be very small.

    The observed PMSE were rather intensive and extended over the 80–90km height interval. PMSE almost disappeared above 86km at the time of greatest Joule heating on 15 July 2000. Neither ionisation changes, nor Joule/particle heating can explain the PMSE reduction. Transport effects due to the strong electric field are a more likely explanation.

    Key words. Meteorology and atmospheric dynamics (middle atmospheric dynamics, ionosphere (ionospheric disturbances; solar radiation and cosmic ray effects

  11. Evaluating the role of key learning theories in ECHO: a telehealth educational program for primary care providers.

    Science.gov (United States)

    Socolovsky, Carmela; Masi, Christopher; Hamlish, Tamara; Aduana, Glen; Arora, Sanjeev; Bakris, George; Johnson, Daniel

    2013-01-01

    ECHO (Extension for Community Healthcare Outcomes) is a telehealth educational program that uses videoconference technology to train community-based primary care providers (PCP's) on the management of complex, chronic diseases. The main components of ECHO are didactics, case presentations, and case-based learning. ECHO was developed using the key principles of Social Cognitive Theory, Situated Learning Theory, and Community of Practice Theory. In a prior study, we implemented an ECHO curriculum to improve management of resistant hypertension. The goals of the current study were to determine the extent to which the learning theories served as the foundation of the ECHO curriculum and identify opportunities to more effectively incorporate key principles of these theories into the ECHO program. We conducted semi-structured interviews with the nine clinicians who participated in the pilot curriculum. A community-based PCP assisted with question development, analysis, and manuscript preparation. We analyzed the interview transcripts using Directed Content Analysis. Transcript analysis supported the contention that ECHO is based upon Social Cognitive Theory, Situated Learning Theory, and Community of Practice Theory. Comments from study participants highlighted benefits of each theory's principles. Conversely, they also suggested we could improve our implementation of ECHO by adhering more closely to specific learning theory strategies. Our results indicate that ECHO indeed reflects the key tenants of Social Cognitive Theory, Situated Learning Theory, and Community of Practice Theory. Several aspects of our ECHO curriculum can be improved by more complete application of these learning theories.

  12. A novel time series analysis approach for prediction of dialysis in critically ill patients using echo-state networks

    Directory of Open Access Journals (Sweden)

    De Turck F

    2010-01-01

    Full Text Available Abstract Background Echo-state networks (ESN are part of a group of reservoir computing methods and are basically a form of recurrent artificial neural networks (ANN. These methods can perform classification tasks on time series data. The recurrent ANN of an echo-state network has an 'echo-state' characteristic. This 'echo-state' functions as a fading memory: samples that have been introduced into the network in a further past, are faded away. The echo-state approach for the training of recurrent neural networks was first described by Jaeger H. et al. In clinical medicine, until this moment, no original research articles have been published to examine the use of echo-state networks. Methods This study examines the possibility of using an echo-state network for prediction of dialysis in the ICU. Therefore, diuresis values and creatinine levels of the first three days after ICU admission were collected from 830 patients admitted to the intensive care unit (ICU between May 31th 2003 and November 17th 2007. The outcome parameter was the performance by the echo-state network in predicting the need for dialysis between day 5 and day 10 of ICU admission. Patients with an ICU length of stay Results The AUC's in the three developed echo-state networks were 0.822, 0.818, and 0.817. These results were comparable to the results obtained by the SVM and the NB algorithm. Conclusions This proof of concept study is the first to evaluate the performance of echo-state networks in an ICU environment. This echo-state network predicted the need for dialysis in ICU patients. The AUC's of the echo-state networks were good and comparable to the performance of other classification algorithms. Moreover, the echo-state network was more easily configured than other time series modeling technologies.

  13. Evolution of Web Services in EOSDIS: Search and Order Metadata Registry (ECHO)

    Science.gov (United States)

    Mitchell, Andrew; Ramapriyan, Hampapuram; Lowe, Dawn

    2009-01-01

    During 2005 through 2008, NASA defined and implemented a major evolutionary change in it Earth Observing system Data and Information System (EOSDIS) to modernize its capabilities. This implementation was based on a vision for 2015 developed during 2005. The EOSDIS 2015 Vision emphasizes increased end-to-end data system efficiency and operability; increased data usability; improved support for end users; and decreased operations costs. One key feature of the Evolution plan was achieving higher operational maturity (ingest, reconciliation, search and order, performance, error handling) for the NASA s Earth Observing System Clearinghouse (ECHO). The ECHO system is an operational metadata registry through which the scientific community can easily discover and exchange NASA's Earth science data and services. ECHO contains metadata for 2,726 data collections comprising over 87 million individual data granules and 34 million browse images, consisting of NASA s EOSDIS Data Centers and the United States Geological Survey's Landsat Project holdings. ECHO is a middleware component based on a Service Oriented Architecture (SOA). The system is comprised of a set of infrastructure services that enable the fundamental SOA functions: publish, discover, and access Earth science resources. It also provides additional services such as user management, data access control, and order management. The ECHO system has a data registry and a services registry. The data registry enables organizations to publish EOS and other Earth-science related data holdings to a common metadata model. These holdings are described through metadata in terms of datasets (types of data) and granules (specific data items of those types). ECHO also supports browse images, which provide a visual representation of the data. The published metadata can be mapped to and from existing standards (e.g., FGDC, ISO 19115). With ECHO, users can find the metadata stored in the data registry and then access the data either

  14. Optimization of diffusion-weighted single-refocused spin-echo EPI by reducing eddy-current artifacts and shortening the echo time.

    Science.gov (United States)

    Shrestha, Manoj; Hok, Pavel; Nöth, Ulrike; Lienerth, Bianca; Deichmann, Ralf

    2018-03-30

    The purpose of this work was to optimize the acquisition of diffusion-weighted (DW) single-refocused spin-echo (srSE) data without intrinsic eddy-current compensation (ECC) for an improved performance of ECC postprocessing. The rationale is that srSE sequences without ECC may yield shorter echo times (TE) and thus higher signal-to-noise ratios (SNR) than srSE or twice-refocused spin-echo (trSE) schemes with intrinsic ECC. The proposed method employs dummy scans with DW gradients to drive eddy currents into a steady state before data acquisition. Parameters of the ECC postprocessing algorithm were also optimized. Simulations were performed to obtain minimum TE values for the proposed sequence and sequences with intrinsic ECC. Experimentally, the proposed method was compared with standard DW-trSE imaging, both in vitro and in vivo. Simulations showed substantially shorter TE for the proposed method than for methods with intrinsic ECC when using shortened echo readouts. Data of the proposed method showed a marked increase in SNR. A dummy scan duration of at least 1.5 s improved performance of the ECC postprocessing algorithm. Changes proposed for the DW-srSE sequence and for the parameter setting of the postprocessing ECC algorithm considerably reduced eddy-current artifacts and provided a higher SNR.

  15. Application of fast spin-echo T2-weighted imaging for examination of the neurocranium. Comparison with the conventional T2-weighted spin-echo sequence

    International Nuclear Information System (INIS)

    Siewert, C.; Hosten, N.; Felix, R.

    1994-01-01

    T 2 -weighted spin-echo imaging is the standard screening procedure in MR imaging of the neutrocranium. We evaluated fast spin-echo T 2 -weighted imaging (TT 2 ) of the neurocranium in comparison to conventional spin-echo T 2 -weighted imaging (T 2 ). Signal-to-noise and contrast-to-noise ratio of normal brain tissues (basal ganglia, grey and white matter, CSF fluid) and different pathologies were calculated. Signal-to-noise ratio and contrast-to-noise ratio were significantly higher than TT 2 than in T 2 (with the exception of grey-to-white matter contrast). Tissues with increased content of water protons (mobile protons) showed the highest contrast to surrounding tissues. The increased signal intensity of fat must be given due attention in fatty lesions. Because the contrast-to-noise ratio between white matter and basal ganglia is less in TT 2 , Parkinson patients have to be examined by conventional T 2 . If these limitations are taken into account, fast spin-echo T 2 -weighted imaging is well appropriate for MR imaging of the neurocranium, resulting in heavy T 2 -weighting achieved in a short acquisition time. (orig.) [de

  16. Optimization image of magnetic resonance imaging (MRI) T2 fast spin echo (FSE) with variation echo train length (ETL) on the rupture tendon achilles case

    Science.gov (United States)

    Muzamil, Akhmad; Haries Firmansyah, Achmad

    2017-05-01

    The research was done the optimization image of Magnetic Resonance Imaging (MRI) T2 Fast Spin Echo (FSE) with variation Echo Train Length (ETL) on the Rupture Tendon Achilles case. This study aims to find the variations Echo Train Length (ETL) from the results of ankle’s MRI image and find out how the value of Echo Train Length (ETL) works on the MRI ankle to produce optimal image. In this research, the used ETL variations were 12 and 20 with the interval 2 on weighting T2 FSE sagittal. The study obtained the influence of Echo Train Length (ETL) on the quality of ankle MRI image sagittal using T2 FSE weighting and analyzed in 25 images of five patients. The data analysis has done quantitatively with the Region of Interest (ROI) directly on computer MRI image planes which conducted statistical tests Signal to Noise Ratio (SNR) and Contras to Noise Ratio (CNR). The Signal to Noise Ratio (SNR) was the highest finding on fat tissue, while the Contras to Noise Ratio (CNR) on the Tendon-Fat tissue with ETL 12 found in two patients. The statistics test showed the significant SNR value of the 0.007 (pTendon tissue, 0.364 (p>0.05) of the Fat, 0.912 (p>0.05) of the Fibula, and 0.436 (p>0.05) of the Heel Bone. For the contrast to noise ratio (CNR) of the Tendon-FAT tissue was about 0.041 (p>0.05). The results of the study showed that ETL variation with T2 FSE sagittal weighting had difference at Tendon tissue and Tendon-Fat tissue for MRI imaging quality. SNR and CNR were an important aspect on imaging optimization process to give the diagnose information.

  17. Meteor head echo polarization at 930 MHz studied with the EISCAT UHF HPLA radar

    Directory of Open Access Journals (Sweden)

    G. Wannberg

    2011-06-01

    Full Text Available The polarization characteristics of 930-MHz meteor head echoes have been studied for the first time, using data obtained in a series of radar measurements carried out with the tristatic EISCAT UHF high power, large aperture (HPLA radar system in October 2009. An analysis of 44 tri-static head echo events shows that the polarization of the echo signal recorded by the Kiruna receiver often fluctuates strongly on time scales of tens of microseconds, illustrating that the scattering process is essentially stochastic. On longer timescales (> milliseconds, more than 90 % of the recorded events show an average polarization signature that is independent of meteor direction of arrival and echo strength and equal to that of an incoherent-scatter return from underdense plasma filling the tristatic observation volume. This shows that the head echo plasma targets scatter isotropically, which in turn implies that they are much smaller than the 33-cm wavelength and close to spherically symmetric, in very good agreement with results from a previous EISCAT UHF study of the head echo RCS/meteor angle-of-incidence relationship. Significant polarization is present in only three events with unique target trajectories. These all show a larger effective target cross section transverse to the trajectory than parallel to it. We propose that the observed polarization may be a signature of a transverse charge separation plasma resonance in the region immediately behind the meteor head, similar to the resonance effects previously discussed in connection with meteor trail echoes by Herlofson, Billam and Browne, Jones and Jones and others.

  18. The novel echo-guided ProGlide technique during percutaneous transfemoral transcatheter aortic valve implantation.

    Science.gov (United States)

    Honda, Yohsuke; Araki, Motoharu; Yamawaki, Masahiro; Tokuda, Takahiro; Tsutumi, Masakazu; Mori, Shinsuke; Sakamoto, Yasunari; Kobayashi, Norihiro; Hirano, Keisuke; Ito, Yoshiaki

    2018-04-01

    The aim of this study was to assess clinical benefit of the Echo-guided ProGlide technique in patients undergoing percutaneous transfemoral transcatheter aortic valve implantation (TF-TAVI). The efficacy of the Echo-guided ProGlide technique during percutaneous TF-TAVI was not previously clarified. A total of 121 consecutive patients who underwent percutaneous TF-TAVI at our institution between February 2014 and July 2017 were enrolled in this study. According to the introduction of this novel technique in March 2016, patients were divided into two groups (echo-guided group who underwent TAVI from March 2016 to July 2017, n = 63; not echo-guided group who underwent TAVI from February 2014 to February 2016, n = 58). The incidence of major vascular complications, defined per the Valve Academic Research Consortium-2 criteria, and ProGlide complications including acute femoral artery stenosis or occlusion and bleeding requiring any intervention. The incidence of major vascular complication and ProGlide complication were significantly lower in the echo-guided group than in not echo-guided group (1.6% vs 17.2%, P guided ProGlide technique was independently associated with prevention of ProGlide complications (odds ratio, 0.11; 95% confidential interval, 0.01-0.76; P = 0.03). This novel Echo-guided ProGlide technique was associated with a lower rate of major vascular complications, particularly ProGlide complications during percutaneous TF-TAVI. © 2017, Wiley Periodicals, Inc.

  19. Comparison of conventional spin-echo, turbo spin-echo and respiratory-triggering turbo spin-echo pulse sequences for T2-weighted MR imaging of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Date, Shuji; Kimura, Fumiko; Ito, Katsuhide.

    1996-01-01

    T 2 -weighted conventional spin-echo (CSE), turbo spin-echo (TSE) and respiratory-triggering turbo spin-echo (RT-TSE) images were compared to determine there efficacy in the diagnosis of hepatocellular carcinoma (HCC). A total of 32 patients with 40 HCCs was examined in this study. Both CSE and RT-TSE images were obtained in all the patients, and in addition conventional TSE images were obtained in 10 patients with 17 HCCs. Quantitative analysis demonstrated that RT-TSE had the highest lesion-liver contrast-to-noise ratio (7.8) and that CSE had the lowest ratio (5.6) (p<0.001). Since qualitative analysis (tissue contrast and conspicuousness of lesions) showed that TSE was inferior to the other sequences, TSE might be less suitable for the depiction of HCC. RT-TSE, however, had the highest assessment in qualitative analysis probably due to reduced respiratory motion artifacts especially at the subphrenic region and at the area adjacent to the gall bladder. It is concluded from the results of the present study that RT-TSE has a potential value as a routine sequence for the detection of HCC. (author)

  20. An artificial bee colony optimization based matching pursuit approach for ultrasonic echo estimation.

    Science.gov (United States)

    Qi, Ai-Ling; Zhang, Guang-Ming; Dong, Ming; Ma, Hong-Wei; Harvey, David M

    2018-03-07

    Ultrasonic echo estimation is important in ultrasonic non-destructive evaluation and material characterization. Matching pursuit is one of the most popular methods for the purpose of estimating ultrasonic echoes. In this paper, an artificial bee colony optimization based matching pursuit approach (ABC-MP) is proposed specifically for ultrasonic signal decomposition by integrating the artificial bee colony algorithm into the matching pursuit method. The optimal atoms are searched from a continuous parameter space over a tailored Gabor dictionary in ABC-MP instead of a discrete parameter space in matching pursuit. As a result, echoes characterized by a set of physical parameters can be estimated accurately and efficiently. The performance of ABC-MP is tested using both simulated signals and real ultrasonic signals, and compared with matching pursuit. Results clearly demonstrate the superior performance of the proposed ABC-MP approach over matching pursuit in ultrasonic echo estimation in terms of the shape and amplitude of the recovered echoes and the reconstructed signal, and the residue signal. Copyright © 2018. Published by Elsevier B.V.

  1. On the factors controlling occurrence of F-region coherent echoes

    Directory of Open Access Journals (Sweden)

    D. W. Danskin

    Full Text Available Several factors are known to control the HF echo occurrence rate, including electron density distribution in the ionosphere (affecting the propagation path of the radar wave, D-region radio wave absorption, and ionospheric irregularity intensity. In this study, we consider 4 days of CUTLASS Finland radar observations over an area where the EISCAT incoherent scatter radar has continuously monitored ionospheric parameters. We illustrate that for the event under consideration, the D-region absorption was not the major factor affecting the echo appearance. We show that the electron density distribution and the radar frequency selection were much more significant factors. The electron density magnitude affects the echo occurrence in two different ways. For small F-region densities, a minimum value of 1 × 1011 m-3 is required to have sufficient radio wave refraction so that the orthogonality (with the magnetic field lines condition is met. For too large densities, radio wave strong "over-refraction" leads to the ionospheric echo disappearance. We estimate that the over-refraction is important for densities greater than 4 × 1011 m-3. We also investigated the backscatter power and the electric field magnitude relationship and found no obvious relationship contrary to the expectation that the gradient-drift plasma instability would lead to stronger irregularity intensity/echo power for larger electric fields.

    Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; auroral ionosphere

  2. Acoustic Echo and Noise Cancellation System for Hand-Free Telecommunication using Variable Step Size Algorithms

    Directory of Open Access Journals (Sweden)

    V. K. Gupta

    2013-04-01

    Full Text Available In this paper, acoustic echo cancellation with doubletalk detection system is implemented for a hand-free telecommunication system using Matlab. Here adaptive noise canceller with blind source separation (ANC-BSS system is proposed to remove both background noise and far-end speaker echo signal in presence of double-talk. During the absence of double-talk, far-end speaker echo signal is cancelled by adaptive echo canceller. Both adaptive noise canceller and adaptive echo canceller are implemented using LMS, NLMS, VSLMS and VSNLMS algorithms. The normalized cross-correlation method is used for double-talk detection. VSNLMS has shown its superiority over all other algorithms both for double-talk and in absence of double-talk. During the absence of double-talk it shows its superiority in terms of increment in ERLE and decrement in misalignment. In presence of double-talk, it shows improvement in SNR of near-end speaker signal.

  3. Robust and accurate visual echo cancellation in a full-duplex projector-camera system.

    Science.gov (United States)

    Liao, Miao; Yang, Ruigang; Zhang, Zhengyou

    2008-10-01

    In this paper we study the problem of "visual echo" in a full-duplex projector-camera system for telecollaboration applications. Visual echo is defined as the appearance of projected contents observed by the camera. It can potentially saturate the projected contents, similar to audio echo in telephone conversation. Our approach to visual echo cancellation includes an offline calibration procedure that records the geometric and photometric transfer between the projector and the camera in a look-up table. During run-time, projected contents in the captured video are identified using the calibration information and suppressed, therefore achieving the goal of cancelling visual echo. Our approach can accurately handle full-color images under arbitrary reflectance of display surfaces and photometric response of the projector or camera. It is robust to geometric registration errors and quantization effects and is therefore particularly effective for high-frequency contents such as texts and hand drawings. We demonstrate the effectiveness of our approach with a variety of real images in a full-duplex projector-camera system.

  4. On the factors controlling occurrence of F-region coherent echoes

    Directory of Open Access Journals (Sweden)

    D. W. Danskin

    2002-09-01

    Full Text Available Several factors are known to control the HF echo occurrence rate, including electron density distribution in the ionosphere (affecting the propagation path of the radar wave, D-region radio wave absorption, and ionospheric irregularity intensity. In this study, we consider 4 days of CUTLASS Finland radar observations over an area where the EISCAT incoherent scatter radar has continuously monitored ionospheric parameters. We illustrate that for the event under consideration, the D-region absorption was not the major factor affecting the echo appearance. We show that the electron density distribution and the radar frequency selection were much more significant factors. The electron density magnitude affects the echo occurrence in two different ways. For small F-region densities, a minimum value of 1 × 1011 m-3 is required to have sufficient radio wave refraction so that the orthogonality (with the magnetic field lines condition is met. For too large densities, radio wave strong "over-refraction" leads to the ionospheric echo disappearance. We estimate that the over-refraction is important for densities greater than 4 × 1011 m-3. We also investigated the backscatter power and the electric field magnitude relationship and found no obvious relationship contrary to the expectation that the gradient-drift plasma instability would lead to stronger irregularity intensity/echo power for larger electric fields.Key words. Ionosphere (ionospheric irregularities; plasma waves and instabilities; auroral ionosphere

  5. Isolated lower mesospheric echoes seen by medium frequency radar at 70° N, 19° E

    Directory of Open Access Journals (Sweden)

    C. M. Hall

    2006-01-01

    Full Text Available We have noted sporadic instances of strong isolated reflections of medium frequency (MF radar waves from the mesosphere from as low as 50 km altitude and have devised a set of criteria for isolating these apparently anomalous echoes from those normally occurring from progressive partial reflections in the D-region. The object of this study is to map the occurrences of such echoes facilitating comparisons with other observations. For example, the similarity and simultaneity of the echo structure for the 20 January 2005 with VHF radar results presented by Lübken et al. (2006 are particularly striking. In presenting a number of such echo events since 2001 selected from the MF radar dataset (which spans 1997 to present, we find that virtually all echo occurrences coincide with enhanced solar proton fluxes suggesting that substantial ionisation of the mesosphere is a necessary condition. Strong partial reflections of the radio wave in the lower mesosphere combined with seasonally varying total absorption higher up, thus giving false impressions of lower mesospheric layers preferentially in winter, constitute a scenario consistent with our observations.

  6. Layer disturbances and the radio-echo free zone in ice sheets

    Directory of Open Access Journals (Sweden)

    R. Drews

    2009-08-01

    Full Text Available Radio-echo sounding of the Antarctic and Greenlandic ice sheets often reveals a layer in the lowest hundreds of meters above bedrock more or less free of radio echoes, known as the echo-free zone (EFZ. The cause of this feature is unclear, so far lacking direct evidence for its origin. We compare echoes around the EPICA drill site in Dronning Maud Land, Antarctica, with the dielectric properties, crystal orientation fabrics and optical stratigraphy of the EPICA-DML ice core. We find that echoes disappear in the depth range where the dielectric contrast is blurred, and where the coherency of the layers in the ice core is lost due to disturbances caused by the ice flow. At the drill site, the EFZ onset at ~2100 m marks a boundary, below which the ice core may have experienced flow induced disturbances on various scales. The onset may indicate changing rheology which needs to be accounted for in the modeling of ice sheet dynamics.

  7. HTTP-based Search and Ordering Using ECHO's REST-based and OpenSearch APIs

    Science.gov (United States)

    Baynes, K.; Newman, D. J.; Pilone, D.

    2012-12-01

    Metadata is an important entity in the process of cataloging, discovering, and describing Earth science data. NASA's Earth Observing System (EOS) ClearingHOuse (ECHO) acts as the core metadata repository for EOSDIS data centers, providing a centralized mechanism for metadata and data discovery and retrieval. By supporting both the ESIP's Federated Search API and its own search and ordering interfaces, ECHO provides multiple capabilities that facilitate ease of discovery and access to its ever-increasing holdings. Users are able to search and export metadata in a variety of formats including ISO 19115, json, and ECHO10. This presentation aims to inform technically savvy clients interested in automating search and ordering of ECHO's metadata catalog. The audience will be introduced to practical and applicable examples of end-to-end workflows that demonstrate finding, sub-setting and ordering data that is bound by keyword, temporal and spatial constraints. Interaction with the ESIP OpenSearch Interface will be highlighted, as will ECHO's own REST-based API.

  8. Biosonar resolving power: Echo-acoustic perception of surface structures in the submillimeter range

    Directory of Open Access Journals (Sweden)

    Ralph eSimon

    2014-02-01

    Full Text Available The minimum distance for which two points still can be separated from each other defines the resolving power of a visual system. In an echo-acoustic context, the resolving power is usually measured as the smallest perceivable distance of two reflecting surfaces on the range axis and is found to be around half a millimetre for bats employing frequency modulated echolocation calls. Only few studies measured such thresholds with physical objects, most often bats were trained on virtual echoes i.e. echoes generated and played back by a computer; moreover, bats were sitting while they received the stimuli. In these studies differences in structure depth between 200 µm and 340 µm were found. However, these low thresholds were never verified for free-flying bats and real physical objects. Here, we show behavioural evidence that the echo-acoustic resolving power for surface structures in fact can be as low as measured for computer generated echoes and even lower, sometimes below 100 µm. We found this exceptional fine discrimination ability only when one of the targets showed spectral interferences in the frequency range of the bats' echolocation call while the other target did not. This result indicates that surface structure is likely to be perceived as a spectral quality rather than being perceived strictly in the time domain. Further, it points out that sonar resolving power directly depends on the highest frequency/shortest wavelength of the signal employed.

  9. Gaussian-approximation formalism for evaluating decay of NMR spin echoes

    International Nuclear Information System (INIS)

    Recchia, C.H.; Gorny, K.; Pennington, C.H.

    1996-01-01

    We present a formalism for evaluating the amplitude of the NMR spin echo and stimulated echo as a function of pulse spacings, for situations in which the nuclear spins experience an effective longitudinal magnetic field h z (t) resulting from an arbitrary number of independent sources, each characterized by its own arbitrary time correlation function. The distribution of accumulated phase angles for the ensemble of nuclear spins at the time of the echo is approximated as a Gaussian. The development of the formalism is motivated by the need to understand the transverse relaxation of 89 Y in YBa 2 Cu 3 O 7 , in which the 89 Y experiences 63,65 Cu dipolar fields which fluctuate due to 63,65 Cu T 1 processes. The formalism is applied successfully to this example, and to the case of nuclei diffusing in a spatially varying magnetic field. Then we examine a situation in which the approximation fails emdash the classic problem of chemical exchange in dimethylformamide, where the methyl protons experience a chemical shift which fluctuates between two discrete values. In this case the Gaussian approximation yields a monotonic decay of the echo amplitude with increasing pulse spacing, while the exact solution yields distinct open-quote open-quote beats close-quote close-quote in the echo height, which we confirm experimentally. In light of this final example the limits of validity of the approximation are discussed. copyright 1996 The American Physical Society

  10. Tropical echo-top height for precipitating clouds observed by multiple active instruments aboard satellites

    Science.gov (United States)

    Chen, Yilun; Fu, Yunfei

    2018-01-01

    The echo-top height observed by the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) has been used by some studies as an approximate calculation of the precipitating-cloud-top height to simulate radiative forcing or to identify overshooting convection. However, due to the low sensitivity ( 17 dBZ) of PR, the PR-echo-top height is lower than the actual precipitating-cloud-top height. Here, the echo-top heights of the tropical precipitating cloud detected by PR, the Cloud Profiling Radar (CPR), and the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) were investigated to evaluate the underestimation of the PR-echo-top height to the actual precipitating-cloud-top height. The results show that there were significant spatial variations in the underestimates of precipitating-cloud-top height by PR. The model simulation showed that these underestimates led to an underestimation of the radiative forcing of the Earth system, the relative error of which was 10% with 1-km underestimation and 20% to 80% with 7-km underestimation when the cloud optical thickness was fixed to 10. Therefore, the underestimates of precipitating-cloud-top height by PR should be taken into consideration when using PR-echo-top height.

  11. Simultaneous observations of noctilucent clouds and polar mesosphere summer echoes at Syowa Station, Antarctica

    Directory of Open Access Journals (Sweden)

    Keisuke Hosokawa

    2013-11-01

    Full Text Available This paper reports simultaneous observations of visible noctilucent clouds (NLC and polar mesosphere summer echoes (PMSE at Syowa Station (69°01′S, 38°61′E in Antarctica. During a 1.5 h interval from 2000 to 2130 UT (2300 to 0030 LT on Feb. 11, 2009, visible NLC were observed south of Syowa Station. The oblique sounding HF radar of SuperDARN at Syowa Station simultaneously observed peculiar echoes in the closest two range gates. The echoes had a small Doppler velocity and a narrow spectral width, which are consistent with the characteristics of PMSE in the SuperDARN data. The simultaneous appearance of the visible NLC and peculiar near-range echoes observed by the HF radar suggests that the echoes were actually a signature of PMSE in the HF band. In addition, the data from the simultaneous measurements show that the spatial distributions of NLC and PMSE in the HF band were collocated with each other, which implies that oblique sounding HF radar is a useful tool for estimating the two-dimensional horizontal distribution of PMSE.

  12. Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)

    Energy Technology Data Exchange (ETDEWEB)

    Rest, A; Welch, D L; Suntzeff, N B; Oaster, L; Lanning, H; Olsen, K; Smith, R C; Becker, A C; Bergmann, M; Challis, P; Clocchiatti, A; Cook, K H; Damke, G; Garg, A; Huber, M E; Matheson, T; Minniti, D; Prieto, J L; Wood-Vasey, W M

    2008-05-06

    We report the discovery of an extensive system of scattered light echo arclets associated with the recent supernovae in the local neighborhood of the Milky Way: Tycho (SN 1572) and Cassiopeia A. Existing work suggests that the Tycho SN was a thermonuclear explosion while the Cas A supernova was a core collapse explosion. Precise classifications according to modern nomenclature require spectra of the outburst light. In the case of ancient SNe, this can only be done with spectroscopy of their light echo, where the discovery of the light echoes from the outburst light is the first step. Adjacent light echo positions suggest that Cas A and Tycho may share common scattering dust structures. If so, it is possible to measure precise distances between historical Galactic supernovae. On-going surveys that alert on the development of bright scattered-light echo features have the potential to reveal detailed spectroscopic information for many recent Galactic supernovae, both directly visible and obscured by dust in the Galactic plane.

  13. Seasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounder

    KAUST Repository

    Røstad, Anders

    2013-11-01

    We used a moored upward-facing 200 kHz echo sounder to address sedimentation of fecal pellets (FPs) from dielly migrating Meganyctiphanes norvegica. The echo sounder was located on the bottom at 150 m depth in the Oslofjord, Norway, and was cabled to shore for continuous measurements during winter and spring. Records of sinking pellets were for the first time observed with an echo sounder. Seasonal patterns of sedimentation of krill FPs were strongly correlated with data from continuous measurement of fluorescence, which illustrate the development of the spring bloom. Sedimenting particles were first observed as fluorescence values started to increase at the end of February and continued to increase until the bloom suddenly culminated at the end of March. This collapse of the bloom was detected on the echo sounder as a pulse of slowly sinking acoustic targets over a 2 d period. Prior to this event, there was a strong diel pattern in sedimentation, which correlated, with some time lag, with the diel migration of krill foraging at night near the surface. Pellet average sinking speeds ranged between 423 m d−1 and 804 m d−1, with a strong relation to pellet target strength, which is an acoustic proxy for size. This novel approach shows that echo sounders may be a valuable tool in studies of vertical pellet flux and, thereby, carbon flux, providing temporal resolution and direct observation of the sedimentation process, which are not obtained from standard methods.

  14. Echo scintillation index affected by cat-eye target's caliber in FSO communication

    Science.gov (United States)

    Shan, Cong-miao; Sun, Hua-yan; Zhang, Lai-xian

    2013-08-01

    Cat-eye effect has been widely used in active laser detection, optical target identification and free space optical (FSO) communication, but atmospheric turbulence makes laser beam fluctuate, which limits the use of cat-eye effect. The optical aperture has the aperture averaging effect to the detecting laser, which can be used to identify optical targets. Using the flashing theory of spherical wave in the weak atmospheric turbulence, the circular aperture filter function and the Kolmogorov power spectrum, the analytic expression of the echo scintillation index of the cat-eye target of the horizontal path two-way transmission was given in which the cat-eye target were equivalent to a combination of two circular apertures and the detector of cat-eye target was equivalent to a reflecting plane with the reflectivity η when the light is normal incidence. Then the impact of turbulence inner and outer scales to the echo scintillation index and the analytic expression of the echo scintillation index at the receiving aperture were presented using the modified Hill spectrum and the modified Von Karman spectrum. The simulation results show that scintillation index of considering the inner scale is larger compared with that of without considering the inner and outer scales and considering the inner and outer scales. Echo scintillation index shows the tendency of decreasing with the target aperture increases. The echo scintillation index increases with the transmission distance increasing.

  15. Characterization of the collagen component of cartilage repair tissue of the talus with quantitative MRI: comparison of T2 relaxation time measurements with a diffusion-weighted double-echo steady-state sequence (dwDESS)

    Energy Technology Data Exchange (ETDEWEB)

    Kretzschmar, M.; Hainc, N.; Studler, U. [University Hospital Basel, Department of Radiology, Basel (Switzerland); Bieri, O. [University Hospital Basel, Division of Radiological Physics, Basel (Switzerland); Miska, M. [University Hospital, Department of Orthopedics, Heidelberg (Germany); Wiewiorski, M.; Valderrabano, V. [University Hospital Basel, Department of Orthopedic Surgery, Basel (Switzerland)

    2015-04-01

    The purpose of this study was to characterize the collagen component of repair tissue (RT) of the talus after autologous matrix-induced chondrogenesis (AMIC) using quantitative T2 and diffusion-weighted imaging. Mean T2 values and diffusion coefficients of AMIC-RT and normal cartilage of the talus of 25 patients with posttraumatic osteochondral lesions and AMIC repair were compared in a cross-sectional design using partially spoiled steady-state free precession (pSSFP) for T2 quantification, and diffusion-weighted double-echo steady-state (dwDESS) for diffusion measurement. RT and cartilage were graded with modified Noyes and MOCART scores on morphological sequences. An association between follow-up interval and quantitative MRI measures was assessed using multivariate regression, after stratifying the cohort according to time interval between surgery and MRI. Mean T2 of the AMIC-RT and cartilage were 43.1 ms and 39.1 ms, respectively (p = 0.26). Mean diffusivity of the RT (1.76 μm{sup 2}/ms) was significantly higher compared to normal cartilage (1.46 μm{sup 2}/ms) (p = 0.0092). No correlation was found between morphological and quantitative parameters. RT diffusivity was lowest in the subgroup with follow-up >28 months (p = 0.027). Compared to T2-mapping, dwDESS demonstrated greater sensitivity in detecting differences in the collagen matrix between AMIC-RT and cartilage. Decreased diffusivity in patients with longer follow-up times may indicate an increased matrix organization of RT. (orig.)

  16. Tap-length optimization of adaptive filters used in stereophonic acoustic echo cancellation

    DEFF Research Database (Denmark)

    Kar, Asutosh; Swamy, M.N.S.

    2017-01-01

    An adaptive filter with a large number of weights or taps is necessary for stereophonic acoustic echo cancellation (SAEC), depending on the room impulse response and acoustic path where the cancellation is performed. However, a large tap-length results in slow convergence and increases...... is applied to an existing multiple sub-filter-based echo canceller, for which we present a convergence analysis. Computer simulations are also presented, comparing the proposed approach with related work....... of acoustic echo paths. The tap-length optimization is applied to a single long adaptive filter with thousands of coefficients to decrease the total number of weights, which in turn reduces the computational load. To further increase the convergence rate, the proposed tap-length-optimization algorithm...

  17. Echo Planar Diffusion-Weighted Imaging: Possibilities and Considerations with 12- and 32-Channel Head Coils

    Directory of Open Access Journals (Sweden)

    John N Morelli

    2012-01-01

    Full Text Available Interest in clinical brain magnetic resonance imaging using 32-channel head coils for signal reception continues to increase. The present investigation assesses possibilities for improving diffusion-weighted image quality using a 32-channel in comparison to a conventional 12-channel coil. The utility of single-shot (ss and an approach to readout-segmented (rs echo planar imaging (EPI are examined using both head coils. Substantial image quality improvements are found with rs-EPI. Imaging with a 32-channel head coil allows for implementation of greater parallel imaging acceleration factors or acquisition of scans at a higher resolution. Specifically, higher resolution imaging with rs-EPI can be achieved by increasing the number of readout segments without increasing echo-spacing or echo time to the degree necessary with ss-EPI - a factor resulting in increased susceptibility artifact and reduced signal-to-noise with the latter.

  18. Photon echo with a few photons in two-level atoms

    International Nuclear Information System (INIS)

    Bonarota, M; Dajczgewand, J; Louchet-Chauvet, A; Le Gouët, J-L; Chanelière, T

    2014-01-01

    To store and retrieve signals at the single photon level, various photon echo schemes have resorted to complex preparation steps involving ancillary shelving states in multi-level atoms. For the first time, we experimentally demonstrate photon echo operation at such a low signal intensity without any preparation step, which allows us to work with mere two-level atoms. This simplified approach relies on the so-coined ‘revival of silenced echo’ (ROSE) scheme. Low noise conditions are obtained by returning the atoms to the ground state before the echo emission. In the present paper we manage ROSE in photon counting conditions, showing that very strong control fields can be compatible with extremely weak signals, making ROSE consistent with quantum memory requirements. (paper)

  19. Underwater Acoustic Transponders Tracking While Mapping With A Multibeam Echo-Sounder

    Science.gov (United States)

    de Moustier, C. P.; Franzheim, A.; Testa, W.; Burns, J. M.; Foy, R.

    2010-12-01

    A 160 kHz multibeam echo-sounder was used to interrogate and receive the replies from custom-built miniature underwater acoustic transponders attached to the carapace of king crabs in Womens Bay, Alaska. This new application of multibeam echo-sounders combines acoustic tracking and mapping, thus providing environmental context to the tracking information. Each transponder replies with its own coded sequence that stands out from other echoes received by the sonar. Range and bearing of the replies from multiple transponders can be obtained in a single sonar ping. The king crab experiment was done in 25-35 m of water depth, and the system was successfully tested without animals at 190 m depth. Work supported by NOAA's Undersea Research Program Grant G4768, with field work support from NOAA-NMFS/AFSC/RACE and Electronic Navigation Ltd.

  20. Rotation commensurate echo of asymmetric molecules—Molecular fingerprints in the time domain

    Energy Technology Data Exchange (ETDEWEB)

    Chesnokov, E. N., E-mail: chesnok@kinetics.nsc.ru [Institute of Chemical Kinetics and Combustion, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Kubarev, V. V. [Budker Institute of Nuclear Physics, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Koshlyakov, P. V. [Institute of Chemical Kinetics and Combustion, Novosibirsk 630090 (Russian Federation)

    2014-12-29

    Using the pulses of terahertz free electron laser and ultra-fast Schottky diode detectors, we observed the coherent transients within a free induction decay of gaseous nitrogen dioxide NO{sub 2}. The laser excited different sub-bands of rotation spectra of NO{sub 2} containing about 50–70 lines. The free induction signal continued more than 30 ns and consisted of many echo-like bursts duration about 0.2 ns. Unlike the similar effect observed previously for linear and symmetric top molecules, the sequence of echo bursts is not periodic. The values for delay of individual echo are stable, and the set of these delays can be considered as a “molecular fingerprint” in the time domain.

  1. Searching gamma-ray bursts for gravitational lensing echoes - Implications for compact dark matter

    Science.gov (United States)

    Nemiroff, R. J.; Norris, J. P.; Wickramasinghe, W. A. D. T.; Horack, J. M.; Kouveliotou, C.; Fishman, G. J.; Meegan, C. A.; Wilson, R. B.; Paciesas, W. S.

    1993-01-01

    The first available 44 gamma-ray bursts (GRBs) detected by the Burst and Transient Source Experiment on board the Compton Gamma-Ray Observatory have been inspected for echo signals following shortly after the main signal. No significant echoes have been found. Echoes would have been expected were the GRBs distant enough and the universe populated with a sufficient density of compact objects composing the dark matter. Constraints on dark matter abundance and GRB redshifts from the present data are presented and discussed. Based on these preliminary results, a universe filled to critical density of compact objects between 10 exp 6.5 and 10 exp 8.1 solar masses are now marginally excluded, or the most likely cosmological distance paradigm for GRBs is not correct. We expect future constraints to be able either to test currently popular cosmological dark matter paradigms or to indicate that GRBs do not lie at cosmological distances.

  2. Operating Spin Echo in the Quantum Regime for an Atomic-Ensemble Quantum Memory.

    Science.gov (United States)

    Rui, Jun; Jiang, Yan; Yang, Sheng-Jun; Zhao, Bo; Bao, Xiao-Hui; Pan, Jian-Wei

    2015-09-25

    Spin echo is a powerful technique to extend atomic or nuclear coherence times by overcoming the dephasing due to inhomogeneous broadenings. However, there are disputes about the feasibility of applying this technique to an ensemble-based quantum memory at the single-quanta level. In this experimental study, we find that noise due to imperfections of the rephasing pulses has both intense superradiant and weak isotropic parts. By properly arranging the beam directions and optimizing the pulse fidelities, we successfully manage to operate the spin echo technique in the quantum regime by observing nonclassical photon-photon correlations as well as the quantum behavior of retrieved photons. Our work for the first time demonstrates the feasibility of harnessing the spin echo method to extend the lifetime of ensemble-based quantum memories at the single-quanta level.

  3. EchoBASE: an integrated post-genomic database for Escherichia coli.

    Science.gov (United States)

    Misra, Raju V; Horler, Richard S P; Reindl, Wolfgang; Goryanin, Igor I; Thomas, Gavin H

    2005-01-01

    EchoBASE (http://www.ecoli-york.org) is a relational database designed to contain and manipulate information from post-genomic experiments using the model bacterium Escherichia coli K-12. Its aim is to collate information from a wide range of sources to provide clues to the functions of the approximately 1500 gene products that have no confirmed cellular function. The database is built on an enhanced annotation of the updated genome sequence of strain MG1655 and the association of experimental data with the E.coli genes and their products. Experiments that can be held within EchoBASE include proteomics studies, microarray data, protein-protein interaction data, structural data and bioinformatics studies. EchoBASE also contains annotated information on 'orphan' enzyme activities from this microbe to aid characterization of the proteins that catalyse these elusive biochemical reactions.

  4. Fast spine echo and fast fluid attenuated inversion recovery sequences in multiple sclerosis

    International Nuclear Information System (INIS)

    Paolillo, Andrea; Giugni, Elisabetta; Bozzao, Alessandro; Bastianello, Stefano

    1997-01-01

    Fast spin echo (FSE) and fast fluid attenuated inversion recovery (fast-FLAIR) sequences, were compared with conventional spin echo (CSE) in quantitating multiple sclerosis (MS) lesion burden. For each sequence, the total number and volume of MS lesions were calculated in 38 remitting multiple sclerosis patients using a semiautomated lesion detection program. Conventional spin echo, fast spin echo, and fast fluid attenuated inversion recovery image were reported on randomly and at different times by two expert observers. Interobserver differences, the time needed to quantitative multiple sclerosis lesions and lesion signal intensity (contrast-to-noise ratio and overall contrast) were considered. The lesions were classified by site into infratentorial, white matter and cortical/subcortical. A total of 2970 lesions with a volume of 961.7 cm 3 was calculated on conventional spin echo images. Fast spin echo images depicted fewer (16.6%; p < .005) and smaller (24.9%; p < .0001) lesions and the differences were statistically significant. Despite an overall nonsignificant reduction for fast-FLAIR images (-5% and 4.8% for lesion number and volume, respectively), significantly lower values (lesion number: p < 0.1; volume: p < .04)were observed for infratentorial lesions, while significantly higher values were seen for cortical/subcortical lesions (lesion number: p < .01; volume: p < .02). A higher lesion/white matter contrast (p < .002), a significant time saving for lesion burden quantitation (p < .05) and very low interobserver variability were found in favor of fast-FLAIR. Our data suggest that, despite the limitations regarding infratentorial lesions, fast-FLAIR sequences are indicated in R studies because of their good identification of cortical/subcortical lesions, almost complete interobserver agreement, higher contrast-to-noise ratio and limited time needed for semiautomated quantitation

  5. Interferometric Meteor Head Echo Observations using the Southern Argentina Agile Meteor Radar (SAAMER)

    Science.gov (United States)

    Janches, D.; Hocking, W.; Pifko, S.; Hormaechea, J. L.; Fritts, D. C.; Brunini, C; Michell, R.; Samara, M.

    2013-01-01

    A radar meteor echo is the radar scattering signature from the free-electrons in a plasma trail generated by entry of extraterrestrial particles into the atmosphere. Three categories of scattering mechanisms exist: specular, nonspecular trails, and head-echoes. Generally, there are two types of radars utilized to detect meteors. Traditional VHF meteor radars (often called all-sky1radars) primarily detect the specular reflection of meteor trails traveling perpendicular to the line of sight of the scattering trail, while High Power and Large Aperture (HPLA) radars efficiently detect meteor head-echoes and, in some cases, non-specular trails. The fact that head-echo measurements can be performed only with HPLA radars limits these studies in several ways. HPLA radars are very sensitive instruments constraining the studies to the lower masses, and these observations cannot be performed continuously because they take place at national observatories with limited allocated observing time. These drawbacks can be addressed by developing head echo observing techniques with modified all-sky meteor radars. In addition, the fact that the simultaneous detection of all different scattering mechanisms can be made with the same instrument, rather than requiring assorted different classes of radars, can help clarify observed differences between the different methodologies. In this study, we demonstrate that such concurrent observations are now possible, enabled by the enhanced design of the Southern Argentina Agile Meteor Radar (SAAMER) deployed at the Estacion Astronomica Rio Grande (EARG) in Tierra del Fuego, Argentina. The results presented here are derived from observations performed over a period of 12 days in August 2011, and include meteoroid dynamical parameter distributions, radiants and estimated masses. Overall, the SAAMER's head echo detections appear to be produced by larger particles than those which have been studied thus far using this technique.

  6. Segmental dynamics of polyethylene-alt-propylene studied by NMR spin echo techniques

    Science.gov (United States)

    Lozovoi, A.; Mattea, C.; Hofmann, M.; Saalwaechter, K.; Fatkullin, N.; Stapf, S.

    2017-06-01

    Segmental dynamics of a highly entangled melt of linear polyethylene-alt-propylene with a molecular weight of 200 kDa was studied with a novel proton nuclear magnetic resonance (NMR) approach based upon 1H → 2H isotope dilution as applied to a solid-echo build-up function ISE(t), which is constructed from the NMR spin echo signals arising from the Hahn echo (HE) and two variations of the solid-echo pulse sequence. The isotope dilution enables the separation of inter- and intramolecular contributions to this function and allows one to extract the segmental mean-squared displacements in the millisecond time range, which is hardly accessible by other experimental methods. The proposed technique in combination with time-temperature superposition yields information about segmental translation in polyethylene-alt-propylene over 6 decades in time from 10-6 s up to 1 s. The time dependence of the mean-squared displacement obtained in this time range clearly shows three regimes of power law with exponents, which are in good agreement with the tube-reptation model predictions for the Rouse model, incoherent reptation and coherent reptation regimes. The results at short times coincide with the fast-field cycling relaxometry and neutron spin echo data, yet, significantly extending the probed time range. Furthermore, the obtained data are verified as well by the use of the dipolar-correlation effect on the Hahn echo, which was developed before by the co-authors. At the same time, the amplitude ratio of the intermolecular part of the proton dynamic dipole-dipole correlation function over the intramolecular part obtained from the experimental data is not in agreement with the predictions of the tube-reptation model for the regimes of incoherent and coherent reptation.

  7. Stabilization of perceived echo amplitudes in echolocating bats. I. Echo detection and automatic gain control in the big brown bat, Eptesicus fuscus, and the fishing bat, Noctilio leporinus.

    Science.gov (United States)

    Hartley, D J

    1992-02-01

    Previous research on echo detection in bats has suggested that the effective threshold is a function of the acoustic clutter in the experimental environment, as might be expected given the low ambient noise levels typical of such psychophysical research. This paper demonstrates that theory of signal detectability (TSD) methodology is applicable to bats and uses it to show that an important element of clutter limiting in Eptesicus fuscus and Noctilio leporinus is backward masking of phantom targets by the real echo from the loudspeakers used to generate them. This information suggests that a previous estimate of the magnitude of automatic gain control (AGC) is too high, due to variable backward masking inherent in the experimental method used. A re-examination of gain control using a masking-free method shows that it reduces auditory sensitivity by 6 to 7 dB per halving of target range, rather than 11 dB as previously thought.

  8. Fast method of NMR imaging based on trains of spin echoes

    International Nuclear Information System (INIS)

    Hennel, F.

    1993-01-01

    A theoretical introduction to Fourier NMR imaging and a discussion of fast methods are presented. Then an application of the method of echo-planar imaging (EPI) with spin echoes in a micro-imaging system is described together with introduced modifications of the sequence. A new technique for the measurement of flow profiles in liquids which results from a modification of x-pulsed EPI is presented. The development of new software for a NMR micro-imaging system is described, too. 51 refs, 29 refs

  9. A Framework for Music-Speech Segregation using Music Fingerprinting and Acoustic Echo Cancellation Principle

    International Nuclear Information System (INIS)

    Hussain, F.; Habib, H. A.; Khan, M. J.

    2015-01-01

    Background interference creates voice intelligibility issue for listerner. This research work considers background music as interference for communication through smart phone in areas with loud background music. This paper proposes a novel framework for background music segregation from human speech using music fingerprinting and acoustic echo cancellation. Initially, background music is searched in the database by music fingerprinting. Identified background music is registered and segregated using acoustic echo cancellation. Proposed approach generates better quality music speech segregation than existing algorithms. The research work is novel and segregates background music completely in comparison to existing approaches where single instruments are segregated successfully. (author)

  10. Design of an Improved Echo Canceller System Based on Internet of Things

    Science.gov (United States)

    Li, Yi; Lu, Yi; An, Douwa

    This paper focuses on a modified echo canceller system developed to satisfy the requirements of long network time-delay in the Internet of Things. The NLMS algorithm used in it is modified to reduce the computational complexity with the characteristics of fast convergence speed and low steady-state mean-square error (MSE). Hardware platform and software program have been designed to verify this algorithm. The simulation results by MATLAB and practical system are presented in support of the feasibility and validity of the proposed algorithm and echo canceller system.

  11. Adverse reactions after the use of sulphur hexafluoride (SonoVue) echo contrast agent.

    Science.gov (United States)

    Geleijnse, Marcel L; Nemes, Attila; Vletter, Wim B; Michels, Michelle; Soliman, Osama I I; Caliskan, Kadir; Galema, Tjebbe W; ten Cate, Folkert J

    2009-01-01

    The aim of the present study was to analyse the adverse effects of SonoVue echo contrast in a consecutive series of 352 cardiac patients during a 4-year period. During 352 consecutive cardiac SonoVue studies, seven patients (2.0%) experienced adverse effects. Four patients (1.1%) had mild allergic reactions causing skin erythema and mild sinus tachycardia, and three patients (0.9%) experienced a severe allergic reaction resulting in (nonfatal) shock. The reported incidence of adverse effects of SonoVue echo contrast in this consecutive series of cardiac patients seems markedly higher than those reported in a company postmarketing analysis.

  12. Development of Instrumentation for Spin-Echo Induced Spatial Beam Modulations

    DEFF Research Database (Denmark)

    Sales, Morten

    orientation of the neutron as it has been shown in Spin-Echo Small Angle Neutron Scattering (SESANS). Taking this technique further we have shown that it is possible to perform quantitative Dark-Field Imaging, where the small angle scattering signal of individual areas in a neutron image can be obtained......Spin-Echo Modulated Small Angle Neutron Scattering in Time-of-Flight mode (ToF SEMSANS) is an emerging technique extending the measurable phase space covered by neutron scattering. Using inclined magnetic field surfaces, (very) small angle scattering from a sample can be mapped into the spin...

  13. OpenSearch (ECHO-ESIP) & REST API for Earth Science Data Access

    Science.gov (United States)

    Mitchell, A.; Cechini, M.; Pilone, D.

    2010-12-01

    This presentation will provide a brief technical overview of OpenSearch, the Earth Science Information Partners (ESIP) Federated Search framework, and the REST architecture; discuss NASA’s Earth Observing System (EOS) ClearingHOuse’s (ECHO) implementation lessons learned; and demonstrate the simplified usage of these technologies. SOAP, as a framework for web service communication has numerous advantages for Enterprise applications and Java/C# type programming languages. As a technical solution, SOAP has been a reliable framework on top of which many applications have been successfully developed and deployed. However, as interest grows for quick development cycles and more intriguing “mashups,” the SOAP API loses its appeal. Lightweight and simple are the vogue characteristics that are sought after. Enter the REST API architecture and OpenSearch format. Both of these items provide a new path for application development addressing some of the issues unresolved by SOAP. ECHO has made available all of its discovery, order submission, and data management services through a publicly accessible SOAP API. This interface is utilized by a variety of ECHO client and data partners to provide valuable capabilities to end users. As ECHO interacted with current and potential partners looking to develop Earth Science tools utilizing ECHO, it became apparent that the development overhead required to interact with the SOAP API was a growing barrier to entry. ECHO acknowledged the technical issues that were being uncovered by its partner community and chose to provide two new interfaces for interacting with the ECHO metadata catalog. The first interface is built upon the OpenSearch format and ESIP Federated Search framework. Leveraging these two items, a client (ECHO-ESIP) was developed with a focus on simplified searching and results presentation. The second interface is built upon the Representational State Transfer (REST) architecture. Leveraging the REST architecture, a

  14. USING A MOBILE RADIO ECHO SOUNDER TO MEASURE BEDROCK TOPOGRAPHY IN EAST QUEEN MAUD LAND, ANTARCTICA

    OpenAIRE

    マエノ, ヒデオ; カミヤマ, コウキチ; フルカワ, テルオ; ワタナベ, オキツグ; ナルセ, レンジ; オカモト, ケンイチ; スイツ, タケシ; ウラツカ, セイホ; Hideo, MAENO; Kokichi, KAMIYAMA; Teruo, FURUKAWA; Okitsugu, WATANABE; Renji, NARUSE; Kenichi, OKAMOTO; Takeshi, SUITZ

    1994-01-01

    As part of the Dome-Fuji Project, the topography of the bedrock over a wide area around Dome-F and along routes from Dome-F to S16 (about 1000 km distance) was surveyed by radio echo sounder with a continuous recording system. The bedrock topography was successfully measured under ice sheets thicker than 3500m, and the performance of the radio echo sounder was confirmed. The highest point of Dome-F was located in the basin like topography of the bedrock, surrounded by more elevated areas. The...

  15. Long term observations of polar mesospheric echoes at Andøya

    Science.gov (United States)

    Latteck, Ralph; Strelnikova, Irina; Renkwitz, Toralf; Sommer, Svenja

    2016-04-01

    Polar mesosphere summer echoes (PMSE) are strong enhancements of received signal power at very high radar frequencies occurring at altitudes between about 80 and 95 km at polar latitudes during summer. These echoes are caused by inhomogeneities in the electron density of the radar Bragg scale within the plasma of the cold summer mesopause region in the presence of negatively charged ice particles. Thus the occurrence of PMSE contains information about mesospheric temperature and water vapour content but also depends on the ionisation due to solar electromagnetic radiation and precipitating high energetic particles. Continuous observations of PMSE have been done on the North-Norwegian island Andøya (69.3°N, 16.0°E) since 1994 using different VHF radars. The PMSE occurrence rate is positively correlated with the geomagnetic Ap index, however not correlated with the solar Lyman α radiation and shows a significant positive trend during the time interval from 1994 until 2012. VHF radar echoes have been observed also during winter times but in the mid mesosphere from about 55 to 85 km altitude. These so called polar mesosphere winter echoes (PMWE) have been observed continuously at Andøya since 2004 using the ALWIN VHF radar (until 2008) and the Middle Atmosphere Alomar Radar System MAARSY (since 2011). Using the more sensitive MAARSY compared to the previous VHF radar systems operated at the site, results in more detections characterized by smaller volume reflectivity values down to 4 ṡ 10-18m-1. The end of the winter season is now hard to determine since mesospheric echoes have also been observed below altitudes of 80 km during non winter months, particularly around the end of May, i.e. the beginning of the polar mesospheric summer echo season. These observations indicate that the physical mechanism for creating the lower mesospheric echoes is present during the early summer months as well. We present results from long term observations of polar mesospheric

  16. Ultrasonic waves scattering through dissimilar welds: application to characterisation of spurious echoes detected during inspection

    International Nuclear Information System (INIS)

    Ahmed, F.

    1999-01-01

    Ultrasonic testing of bimetallic welds can show the presence of structural echoes. In pulse echo mode inspections at oblique incidence, these echoes are detected close to the back-wall (surface opposite to the control). These echoes have a specific shape: the amplitude is distributed along lines parallel to the weld sides. Such echoes can disturb the inspection: they can be misinterpreted as provided by a defect, or they can mask a possible defect. The aim of this thesis is to explain this phenomenon with an interpretation based on the anisotropic property of the weld. In such a structure, specific mode conversions in the lasts welding pass arise. Mode converted waves can reflect normally on the back-wall and therefore back propagate to the transducer along the same wave path as the forward propagation. Some generalities of ultrasonic testing of bimetallic welds are given in a preliminary chapter. In the first chapter, various experiments showed that these structural echoes do not result from beam deflection in the weld and that this phenomenon occurs in the last millimeters under the back-wall. According to these results, an interpretation for these echoes based on the anisotropic and the inhomogeneous structure of the weld is given in the last welding pass, oblique compression waves may be converted into normal shear waves. The second chapter presented a theoretical analysis of these mode conversions phenomenon between two metallurgical structures with different dendrite orientations. The analysis of the welding passes metallography and a bibliographic study summarizes on the relevancy to use a orthotropic symmetry to describe the metallurgical structure of the material under test. The third chapter deals with experimental studies to confirm this hypothesis. Detection of shear waves in the last welding passes near the back-wall mock-up using a specific sensor, able to discriminate the polarisation wave at the reception, validate the mode conversion hypothesis

  17. A single-shot T2mapping protocol based on echo-split gradient-spin-echo acquisition and parametric multiplexed sensitivity encoding based on projection onto convex sets reconstruction.

    Science.gov (United States)

    Chu, Mei-Lan; Chang, Hing-Chiu; Oshio, Koichi; Chen, Nan-Kuei

    2018-01-01

    To develop a high-speed T 2 mapping protocol that is capable of accurately measuring T 2 relaxation time constants from a single-shot acquisition. A new echo-split single-shot gradient-spin-echo (GRASE) pulse sequence is developed to acquire multicontrast data while suppressing signals from most nonprimary echo pathways in Carr-Purcell-Meiboom-Gill (CPMG) echoes. Residual nonprimary pathway signals are taken into consideration when performing T 2 mapping using a parametric multiplexed sensitivity encoding based on projection onto convex sets (parametric-POCSMUSE) reconstruction method that incorporates extended phase graph modeling of GRASE signals. The single-shot echo-split GRASE-based T 2 mapping procedure was evaluated in human studies at 3 Tesla. The acquired data were compared with reference data obtained with a more time-consuming interleaved spin-echo echo planar imaging protocol. T 2 maps derived from conventional single-shot GRASE scans, in which nonprimary echo pathways were not appropriately addressed, were also evaluated. Using the developed single-shot T 2 mapping protocol, quantitatively accurate T 2 maps can be obtained with a short scan time (parametric-POCSMUSE reconstruction. Magn Reson Med 79:383-393, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  18. Diffusion-prepared stimulated-echo turbo spin echo (DPsti-TSE): An eddy current-insensitive sequence for three-dimensional high-resolution and undistorted diffusion-weighted imaging

    NARCIS (Netherlands)

    Zhang, Qinwei; Coolen, Bram F.; Versluis, Maarten J.; Strijkers, Gustav J.; Nederveen, Aart J.

    2017-01-01

    In this study, we present a new three-dimensional (3D), diffusion-prepared turbo spin echo sequence based on a stimulated-echo read-out (DPsti-TSE) enabling high-resolution and undistorted diffusion-weighted imaging (DWI). A dephasing gradient in the diffusion preparation module and rephasing

  19. Liver T2-weighted MR imaging: assessment of a three-dimensional fast spin-echo with extended echo train acquisition sequence at 1.5 Tesla.

    Science.gov (United States)

    Denoiseux, Céline Cotereau; Boulay-Coletta, Isabelle; Nakache, Jean-Pierre; Claude, Isabelle Dufour; Zins, Marc

    2013-08-01

    To retrospectively compare image quality and lesion detectability with two T2-weighted sequences at 1.5 Tesla (T): respiratory-triggered three-dimensional fat sat fast-spin-echo with extended echo-train acquisition (3D FSE-XETA) and respiratory-triggered two-dimensional fat-sat fast recovery fast-spin-echo (2D FRFSE). MR was performed at 1.5T in 53 consecutive patients. Two radiologists blinded to the sequence details reviewed the studies to determine: (i) signal and contrast to noise ratios, (ii) overall image quality, (iii) sensitivity for focal lesion detection. Image assessment scores for the 2D FRFSE sequence were significantly higher than those for the 3D FSE-XETA sequence for overall image quality (P < 0.01) and artifacts (P < 0.001). Sensitivity for liver lesion detection was higher with the 3D FSE-XETA sequence (69.3% versus 57.3%; P < 0.05) compared with the 2D FRFSE sequence. The 3D FSE-XETA sequence improves the reader confidence score (P < 0.01) for liver lesions detection. Inter-observer correlation was higher with the 3D FSE-XETA sequence. For T2-weighted liver imaging at 1.5T, the 3D FSE-XETA sequence improves sensitivity, reader confidence score and interobserver correlation for focal liver lesion detection, but it suffers from a lower overall image quality and higher artifacts. Copyright © 2013 Wiley Periodicals, Inc.

  20. Reduction of B1 sensitivity in selective single-slab 3D turbo spin echo imaging with very long echo trains.

    Science.gov (United States)

    Park, Jaeseok; Mugler, John P; Hughes, Timothy

    2009-10-01

    Single-slab 3D turbo/fast spin echo (SE) imaging with very long echo trains was recently introduced with slab selection using a highly selective excitation pulse and short, nonselective refocusing pulses with variable flip angles for high imaging efficiency. This technique, however, is vulnerable to image degradation in the presence of spatially varying B(1) amplitudes. In this work we develop a B(1) inhomogeneity-reduced version of single-slab 3D turbo/fast SE imaging based on the hypothesis that it is critical to achieve spatially uniform excitation. Slab selection was performed using composite adiabatic selective excitation wherein magnetization is tipped into the transverse plane by a nonselective adiabatic-half-passage pulse and then slab is selected by a pair of selective adiabatic-full-passage pulses. Simulations and experiments were performed to evaluate the proposed technique and demonstrated that this approach is a simple and efficient way to reduce B(1) sensitivity in single-slab 3D turbo/fast SE imaging with very long echo trains. (c) 2009 Wiley-Liss, Inc.